Question 1 :
Effervescence is seen when a bottle of soda water is opened.
Question 2 :
Which part of tooth, made up of calcium phosphate, is the hardest substance in the body?
Question 5 :
When the soil is too basic, plants do not grow well in it. To improve its quality what must be added to the soil?
Question 6 :
$pK_{a}$ of acetic acid is <b>4.741</b>. The concentration of $CH_{3}COONa$ is <b>0.01</b> M. The pH of $CH_{3}COONa$ is?
Question 9 :
Calculate the pH of a solution which is 0.1 M in HA and 0.5M in NaA. Ka for HA is $1.8\times { 10 }^{ -6 }$?
Question 11 :
The hydrogen ion concentration of the oceans is about $2\times10^{-9}\space M$. What is the $pH$?
Question 14 :
Statement I: A basic solution has more hydrogen ions than an acidic solution.<br/>Statement II: pH is defined as the -log $[H^+]$.<br/>
Question 16 :
$p{ K }_{ a }$ values of four acids are given below at ${ 25 }^{ o }C$. The strongest acid is:
Question 17 :
The acid present in the body of red ant is ________.<br/>
Question 20 :
Four solutions A, B, C and D when tested with universal indicator showed pH as $4, 11, 7$ and $9$ respectively. Which one of the four solutions is neutral?<br/>
Question 21 :
Which colour appears when few drops of phenolphthalein put into test tube contains lime water?
Question 22 :
In which of the following reactions does conc.${ H }_{ 2 }S{ O }_{ 4 }$ act as an oxidising agent?
Question 23 :
$1.0 \ L$ solution is prepared by mixing $61 \ gm$ benzonic acid $(pK_a = 4.2)$ with $72 \ gm$ of sodium benzoate and then $\text{300 mL 1.0 M HBr}$ solution was added. the $pH$ of final solution is:-
Question 24 :
Aquaregia is prepared by mixing conc. $HCl$ and $conc. HNO_3$ in the ratio ________ 
Question 25 :
The chloride salt of a certain weak monoacidic organic base is hydrolysed to an extent of $3$% in its $0.1M$ solution at ${25}^{o}C$. Given that the ionic product of water is ${10}^{-14}$ at this temperature, what is the dissociation constant of the base?
Question 28 :
Which of the following methods is adopted for preparing dilute solution of ${ H }_{ 2 }S{ O }_{ 4 }$?
Question 33 :
If tartaric acid is not added in baking powder, the cake will taste bitter due to te presence of -
Question 34 :
The solution of bleaching powder in water is always a clear solution.<br/>
Question 35 :
Water of crystallization is the fixed number of water molecules chemically attached to a unit of a salt in its crystalline form.<br/>
Question 37 :
When $NH_{3}(0.1\ M) 50\ ml$ mix with $HCl (0.1\ M)\ 10\ ml$ then what is $pH$ of resultant solution $(Pk_{b} = 4.75)$.
Question 39 :
If $H^{+}$ion concentration of a solution is increasedby $10$ times, its $pH$ will :<br>
Question 41 :
Assertion: pH of a neutral solution is always $7$.
Reason: pH of a solution does not depend upon temperature.
Question 46 :
On adding which of the following, the pH of $20$ ml of $0.1 N$ $HCl$ will not alter?
Question 47 :
When sample of baking soda is strongly ignited in crucible it suffered loss in weight of  $3.1 g $  the mass of baking soda is- 
Question 52 :
On adding 0.04 g solid $NaOH$ to a 100 ml $\dfrac{M}{200} Ba(OH)_{2}$ solution, determine change in $pH$.
Question 54 :
One of the major constituents of baking powder is sodium hydrogen carbonate, the other constituent is:<br>
Question 55 :
Which of the following is not a use of baking soda?
Question 56 :
If the pH of pure water is $7$, then the hydrogen ion concentration, $[H^{+}]$ in mol L$^{-1}$ will be:
Question 57 :
What is the $pH$ of a $0.200$ M solution of $C_6H_5COONa$? (The $K_a$ of $C_6H_5COOH$ is $6.4\times 10^{-5}$)
Question 58 :
State whether the given statement is true or false:<br/>Bleaching powder contains about 50 % available chlorine.<br/>
Question 61 :
Which one of the following is present as an active ingredient in bleaching powder for bleaching action?
Question 64 :
When we add a pinch of sodium hydrogen carbonate in a flask containing ethanoic acid a reaction takes place. What will be the observation when we carry out the reaction?
Question 67 :
The bleaching action of the bleaching powder is due to liberation of :<br/>
Question 68 :
Cacullate the pH of a $0.2M$ solution of strychnine hydrochloride. $\left( p{ K }_{ b }=1\times { 10 }^{ -7 } \right) $
Question 69 :
The pH of a $0.02M$ ammonia solution which is $5 \%$ ionised will be:
Question 71 :
The bleaching action of the bleaching powder is due to the liberation of 
Question 73 :
$10\ mL$ of a strong acid solution of $pH=2$ are mixed with $990\ mL$ of another acid solution of $pH=4$. The $pH$ of the following solution will be:
Question 75 :
When bleaching powder is dissolved in water, the residue left is :<br/>
Question 76 :
Which one of the following processes does not occur during formation of $CH{ Cl }_{ 3 }$ from ${ C_2 H }_{ 5 }OH$ and bleaching powder?
Question 77 :
$K_a$ for $CH_3COOH$ is $1.8\times 10^{-5}$ and $K_b$ for $NH_4OH$ is $1.8 \times 10^{-5}$. The pH of ammonium acetate will be:<br/>
Question 78 :
What is the minimum $pH$ when $Fe(OH)_3$ starts precipitating from a solution contain $0.1M\ FeCl_3$? $K_{sp}$ $Fe(OH)_3 = 8\times 10^{-13}M^3$
Question 80 :
The reaction of $NaCl$ and $CaCO_3$ gives sodium carbonate. But this reaction cannot be used for the manufacture of washing soda since it is a reversible reaction.<br/>
Question 81 :
Which of the following salts does not contain water of crystallisation?<br>
Question 82 :
Bleaching powder is soluble in cold water giving a milky solution due to:
Question 84 :
To 250.0 mL of M/50$H_{2}SO_{4}$, 4 g of solid $NaOH$ is added and the solution is diluted to 1.0 L. The pH of the resulting solution is:
Question 85 :
Read the given statements and select the correct option:<br/>Statement 1 :Backing soda does not taste sour.<br/>Statement 2 :Bases are sour in taste while acids are bitter in taste.
Question 86 :
The crystalline salt, $Na_{2}SO_{4}xH_{2}O$ on heating losses $55.9\%$ of its weight. The formula of the crystalline salt is :
Question 91 :
Assertion: Sodium bicarbonate is an acidic salt.
Reason: It gives basic solution in water.
Question 92 :
A given weak acid (0.10 M) had $pK_{a}=6$. The pH of the solution is:
Question 93 :
$NaHCO_{3}$ can be used on its own to make cakes or bread. Baking powder is more commonly used, and contains $NaHCO_{3}$, $Ca(H_{2}PO_{4})_{2}$ and starch. An improved combination baking powder contains about 40% starch, 30% $NaHCO_{3}$ 20% $NaAl(SO_{4})_{2}$ and 10% $Ca(H_{2}PO_{4})_{2}.$ Answer the following questions based on above study.<br/>$Ca(H_{2}PO_{4})_{2}$ in baking powder:
Question 94 :
The more commonly used baking powder contains about 30% $NaHCO_3$, 20% $NaAl(SO_4)_2$, 10% $Ca(H_2PO_4)_2$ and 40% starch. Which of the following statements are correct?<br/>
Question 95 :
$1.0$ ml of a solution of $HCl$ with a $pH$ of $4.0$ is added it to $9.0$ ml of distilled water, the $pH$ of the final solution will be:
Question 96 :
The ions responsible for the bleaching action of bleaching powder and the ions responsible for loss of bleaching action of bleaching powder due to the storage for long time respectively are:<br/>
Question 97 :
What is the correct increasing order of the $pH$ values of the following solutions with equal concentrations?
Question 99 :
$NaHCO_{3}$ can be used on its own to make cakes or bread. Baking powder is more commonly used, and contains $NaHCO_{3}$, $Ca(H_{2}PO_{4})_{2}$ and starch. An improved combination baking powder contains about 40% starch, 30% $NaHCO_{3}$ 20% $NaAl(SO_{4})_{2}$ and 10% $Ca(H_{2}PO_{4})_{2}.$ Answer the following questions based on above study.<br/>Rise in bread and cakes is due to______ when it decomposes between $50^{o}C$ and $100^{o}C$. 
Question 100 :
To $1.0 L$ solution containing $0.1$ mol each of $NH_3$ and $NH_4Cl, 0.05$ mol NaOH is added. The change in pH will be : $(pK_a$ for $CH_3 COOH=4.74$)
Question 101 :
When ethyl alcohol is heated with a paste of bleaching powder, we get a compound in which the function of bleaching powder is: 
Question 103 :
The aqueous solution of which one of the following is basic?
Question 104 :
$NaHCO_{3}$ can be used on its own to make cakes or bread. Baking powder is more commonly used, and contains $NaHCO_{3}$, $Ca(H_{2}PO_{4})_{2}$ and starch. An improved combination baking powder contains about 40% starch, 30% $NaHCO_{3}$ 20% $NaAl(SO_{4})_{2}$ and 10% $Ca(H_{2}PO_{4})_{2}$Answer the following questions based on above study.<br/><br/>In improved baking powder, $NaAl(SO_{4})_{2}$ is used for :
Question 105 :
$\dfrac{N}{10}$ acetic acid was titrated with $\dfrac{N}{10}$ $NaOH$. when 25%, 50% and 75% of titration is over then the $pH$ of the solution will be (respectively): $[K_a = 10^5]$ 
Question 108 :
Percentage ionisation of water at certain temperature is $3.6\times { 10 }^{ -7 }$%. Calculate ${K}_{w}$ and $pH$ of water.
Question 110 :
Substance $X$:<br/>(I) reacts with $H_2S$ to produce white turbidity.<br/>(II) changes light green solution of $FeSO_4$ into yellow colour.<br/>(III) reacts with moisture to give pungent smelling gas.<br/>Hence $X$ is:
Question 111 :
The $pH$of $0.1 M$ solution of the following salts increases in the order
Question 113 :
The $pH$ of a ${ 10 }^{ -9 }\ M$ solution of $HCl$ in water is :<br>
Question 114 :
The $pH$ of a buffer solution containing equal molar concentration of a week base and its chloride ($K_{b}$ for weak base $=2\times 10^{-5}$) is :
Question 115 :
Baking powder used to make a cake is a mixture of starch, $NaHCO_3$ and $Ca(H_2PO_4)_2$. The function of $Ca(H_2PO_4)_2$ is:<br/>
Question 117 :
The first and second dissociation constants of an acid $H_{2}A$ are $1.0\times 10^{-5}$ and $5.0\times 10^{-10}$ respectively. The overall dissociation constant of the acid will be:
Question 118 :
The $pH$ of $0.1M$ solution of the following salts increases in the order:
Question 119 :
Iso-electric point of alanine is (pH = $6$). At which pH, maximum concentration of zwitter ion of alanine will be present?
Question 120 :
One mole of ammonia was completely absorbed in one litre solution each of<br/>I. $1\ M\ HCl$<br/>II. $1 \ M\ CH_3COOH$ <br/>III. $1\ M\ H_2SO_4$ at $298$ K<br/>The decreasing order for the $pH$ of the resulting solution is:(Given: $K_b (NH_3) = 4.74$)
Question 122 :
$1\ cc$ of $0.1N$ $HCl$ is added to $1$ litre solution of sodium chloride. The $pH$ of the resulting solution will be:
Question 123 :
Which is the correct for the following reaction: <br/>$B\, (OH)_3\, +\, H_2O\, \rightarrow \, [B(OH)_4]^-\, +\, H^+$
Question 124 :
Which one of the following solutions will have the highest pH value?
Question 125 :
The $pH$ at which a 0.01 M ${ Al }^{ +3 }$ solution is 99.99% precipitated is: $\left( { K }_{ sp } \ \ Al\left( OH \right) _{ 3 }=1\times { 10 }^{ -18 }at\quad 25 \right) $
Question 126 :
When chlorine is passed over dry slaked lime at room temperature, the main reaction product is:
Question 127 :
The $pH$ of $HCl$ is 1. $1.10\ ml$ of this solution is reacted with $40\ ml$ of $NaOH$ solution whose $pH=12$. The $pH$ of resulting solution is: $(\log(1.2)=0.108)$<br/>
Question 128 :
Dissociation constants of $CH_3COOH$ and $NH_4OH$ in aqueous solution are $10^{-5}$. If pH of a $CH_3COOH$ solution is $3$. What will be the pH of $NH_4OH$?
Question 129 :
The third dissociation constant of $H_{3}PO_{4}$ is $1.3\ \times 10^{-12}$. Assume that the hydrolysis proceeds only in the first step, the $pH$ of $0.1\ M\ K_{3}PO_{4}$ solution is:
Question 130 :
Number of $OH^-$ in 1 mL solution of pH = 13 is:
Question 131 :
The indicator constant for an acidic indicator , HIn is $ 5 \times 10^{-6}  M $. this indicator appears only in the colour of acidic from when $ \frac { [In^- ] }{ [HIn]} \le \frac {1}{20} $ and it appears only in the colour of basic form when $ \frac { [HIn]}{[In^-]} \le \frac {1}{40} . $ the pH range of indicator is:
Question 134 :
AB + CD $\rightarrow$ AD + BC<br/><br/>The reaction is an example of _________.<br/><br/><br/>
Question 135 :
$KXO_3$(s) well mixed with water, temperature of solution falls. This reaction is:<br/>
Question 136 : <p>Oils on treating with hydrogen in the presence of palladium or nickel catalyst form fats. This is an example of :</p>
Question 137 :
When chlorine reacts with sodium bromide the solution turns brown because ________.
Question 139 :
What is the difference between displacement over double displacement reactions ?
Question 141 :
An oxidizing agent is always takes part in the reduction process while a reducing agent is always take part in the _______ process.
Question 142 :
Identify the type of reaction which will occur based on the information provided about the reactants:<br>${CH}_{4}(g)+{O}_{2}(g)\rightarrow$
Question 143 :
Which of the following is an example of the exothermic reaction ?
Question 144 :
A chemical reaction in which heat is evolved is called a/an:<br/>
Question 146 :
In the reaction, $4Fe+3O_2\rightleftharpoons 4Fe^{3+}+6O^{2-}$ Which of the following statements is incorrect?
Question 147 :
$FeCl_3 + 3NaOH \rightarrow 3NaCl + Fe(OH)_3$<br/><br/>The reaction is an example of________.
Question 149 :
State true or false.<br/><br/>In redox reactions, oxidation and reduction take place simultaneously.<br/>
Question 151 :
The substance that initially involved in a chemical reaction is called a reactant.
Question 153 :
Which of the following reaction requires oxygen to be a reactant ?
Question 155 :
Which type of chemical decomposition reaction is the following reaction?<br>$Cu(OH)_2\xrightarrow {heat} CuO+H_2O$
Question 156 :
The conversion of ${Cr}_{2}{O}_{7}^{2-}$ to ${Cr}^{3+}$ during a chemical reaction is an example of:
Question 161 :
A less reactive metal replaces a more reactive metal from its salt solution in water.<br>
Question 163 :
Which of the following symbol is used to show solid precipitate?
Question 167 :
Balanced chemical equations imply which of the following?<br>$I$. Numbers of molecules are conserved in chemical change<br>$II$. Numbers of atoms are conserved in chemical change.<br>$III$. Mass is conserved in chemical change.
Question 169 :
Reaction of iron nails with copper sulphate solution is an example of ____________.
Question 170 :
Three cations $A, B, C$ are allowed to react with ammonium hydroxide solution. $A$ and $B$ produce a dirty green precipitate and a reddish brown precipitate respectively, both of which do not dissolve on further addition of ${NH}_{4}OH$. $C$ gives pale blue colour precipitate with less amount of ammonium hydroxide and on further addition of ${NH}_{4}OH$, precipitate becomes soluble and deep blue colour solution is formed:
Question 172 :
Name the type of the following chemical reaction.$2KClO_3 \rightarrow 2KCl +3O_2$
Question 173 :
The reaction of hydrochloric acid with zinc oxide to form zinc chloride and water is neutralization reaction. State whether the statement is true or false
Question 174 :
Other signs of a chemical reaction might be an increase in temperature if heat is released or a change in _____.
Question 176 :
In $HS^, I^, R-NH_2, NH_3$ order of proton excepting tendency will be:
Question 177 :
State true or false.<br/>In a chemical equation, the products are written on the left-hand side and the reactants on the right-hand side with an arrow in between.
Question 178 :
Aqueous solutions of magnesium chloride and silver nitrate are mixed to form solid silver chloride and aqueous magnesium nitrate.<br/><br/>The balanced molecular equation contains which one of the following terms?
Question 180 :
The activity of the metal barium is between that of sodium and potassium. It is likely that:
Question 181 :
Breaking of lead bromide into lead and bromine is an example of _____.
Question 182 :
Assertion: In a reaction<br/><br/>$Z n ( s ) + CuSO_4 (aq) \rightarrow ZnSO_4 (aq) + Cu(s)$<br/><br/>Zn is a reductant but itself get oxidized.
Reason: In a redox reaction, oxidant is reduced by accepting electrons and reductant is oxidized by losing electrons.
Question 187 :
The phenomenon of formation of simple sugar from starch in our body is the example of which reaction? 
Question 189 :
Magnesium reacts with acids producing hydrogen and corresponding magnesium salts. In such reactions Mg undergoes.
Question 190 :
Reaction of iron nails with copper sulphate solution is an example of:<br>
Question 192 :
Which of the statements about the reaction below are incorrect?<br/>$2PbO\left( s \right) +C\left( s \right) \rightarrow 2Pb\left( s \right) +C{ O }_{ 2 }\left( g \right) $<br/>(a) Lead is getting reduced.<br/>(b) Carbon dioxide is getting oxidised.<br/>(c) Carbon is getting oxidised.<br/>(d) Lead oxide is getting reduced.
Question 194 :
Which of the following is(are) an endothermic process(es) ?<br>(i) Dilution of sulphuric acid<br>(ii) Sublimation of dry ice<br>(iii) Condensation of water vapours<br>(iv) Evaporation of water<br>
Question 195 :
Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride. This is a :<br/>
Question 197 :
Name the type of following chemical reaction.$CaCO_3 \rightarrow CaO + CO_2$
Question 199 :
Identify the reducing agent in the redox reaction<br/><br/>$5SO^{2-}_3+ 2MnO^{-}_4 +6H^{+} \rightarrow 5SO^{2-}_4 +2Mn^{2+} +3H_2O$
Question 200 :
Identify the type of the reaction.Potassium + Iron oxide $\rightarrow$ Potassium oxide + Iron
Question 202 :
When calcium nitrate thermally decomposes oxygen is one of the products. Which volume of oxygen is produced under room conditions when $0.50$ mol of calcium nitrate thermally decomposes?
Question 206 :
Name the type of following chemical reaction.$KNO_3 + H_2SO_4 \rightarrow HNO_3 + KHSO_4$
Question 208 :
When sodium sulphate solution reacts with barium chloride solution, the solution after the reaction contains mainly.....
Question 209 :
In a change hydrogen peroxide gives rise' to hydrogen oxide and oxygen. This is an example of:
Question 210 :
In which of the following compounds, an element exhibits two different oxidation states ?
Question 212 :
The reaction between carbon and oxygen can be represented as $C_{(s)}+O_{2(g)}\rightarrow CO_{2(g)}+heat$.<br/><br/>In which of the following type(s), the above reaction can be classified?<br/>I. Combustion reaction<br/>II. Displacement reaction<br/>III. Endothermic reaction<br/>IV. Combination reaction.<br/>
Question 215 :
Which of the following reaction are disproportion reaction?<br/>a) $2Cu^+\rightarrow Cu^{2+}+Cu^o$<br/>b) $3MnO^{2-}_4+4H^+\rightarrow 2MnO_4^-+MnO_2+2H_2O$<br/>c) $2KMnO_4\xrightarrow []{\Delta}K_2MnO_4+MnO_2+O_2$<br/>d) $2MnO_4^-+3Mn^{2+}+2H_2O\rightarrow 5MnO_2+4H^{+}$
Question 216 :
Which of the following are combination reactions?<br>(i)$2 \mathrm{KClO}_{3} \frac{\mathrm{Heat}}{\longrightarrow} 2 \mathrm{KCl}+3 \mathrm{O}_{2}$<br>(ii)$M g O+H_{2} o \rightarrow M g(O H)_{2}$<br>(iii)$4 A 1+3 O_{2} \rightarrow 2 A 1_{2} O_{3}$<br>(iv)$Z n+F e S O_{4} \rightarrow Z n S O_{4}+F e$
Question 217 :
On heating blue coloured powder of copper(II) nitrate in a boiling tube copper oxide (black), oxygen gas and a brown gas X is formed. Which type of reaction is this?<br/>
Question 218 :
Identify the reaction from the following in which physical and chemical changes are occurring:
Question 219 :
Which of the following can act only as a reducing agent?<br>
Question 222 :
Identify the product(s) which will be formed by using the information provided about the reactants :<br/>${C}_{4}{H}_{10}(g)+{O}_{2}(g) \rightarrow$
Question 223 :
$\displaystyle CuO+{ H }_{ 2 }\longrightarrow { H }_{ 2 }O+Cu$, reaction is an example of :<br/>
Question 225 :
The decomposition of mercuric oxide ($Hg)$) on heating, resulting in the formation of mercury and oxygen, is represented by the following chemical equation-<br/>$2HgO+180kJ\longrightarrow 2Hg+{O}_{2}$<br/>Which one of the following represents the heat of formation of mercuric oxide?
Question 226 :
Two aqueous solutions are mixed and a precipitate is formed. What type of reaction is it? 
Question 227 :
Name the type of following chemical reaction.<br/>$PbO_2 + SO_2 \rightarrow PbSO_4$
Question 228 :
The digestion of food in the body is an example of __________ reaction.
Question 231 :
How much $CaO$ is to be added to the furnace charge for each $1280\ kg$ of pure $CaC_{2}$ produced ?
Question 233 :
If the value of $n$ is $2$, then the atomic weight of metal $M$, is
Question 234 :
A quantity of $6\ g\ NaOH$ and $4.4\ g\ CO_{2}$ is allowed to react to form $Na_{2}CO_{3}$ or $NaHCO_{3}$ or both. Which of the following is correct statement regarding the reaction?
Question 236 :
How many grams of ammonium nitrate will be formed in the reaction?
Question 238 :
What amount of $BaSO_4$ can be obtained on mixing 0.5 mole $BaCl_2$ with 1 mole of $H_2SO_4$ ?
Question 239 :
What is not a mole ratio of $ \displaystyle 6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$? <br/>
Question 241 : For the cell $Zn(s) |Zn^{2+} (aq) || M^{x+} (aq) | M(s)$, different half cells and their standard electrode potentials are given below:<br/><table class="wysiwyg-table"><tbody><tr><td>$M^{x+} (aq/M(s))$</td><td>$Au^{3+} (aq)/Au(s)$</td><td>$Ag^+ \, /Ag(s)$</td><td>$Fe^{3+}(aq)/Fe^{2+} (aq)$</td><td>$Fe^{2+}(aq)/Fe(s)$</td></tr><tr><td>$E^o_{M^{x+}/M^{/(V)}}$<br/></td><td>$1.40$</td><td>$0.80$</td><td>$0.77$</td><td>$-0.44$</td></tr></tbody></table><br/>If $E^o_{Zn^{2+}/Zn} = -0.76 V$, which cathode will give a maximum value of $E^o_{cell}$ per electron transferred ?
Question 242 :
An amount of 0.01 mole of $ SO_{2}Cl_{2} $ is hydrolysed completely in sufficientwater (no gas is allowed to escape out ) and the solution is diluted to 200 ml. Which of the following statement is/are correct? (Ag = 108 )
Question 243 :
Minimum amount of $Ag_2CO_3$ (s) required to produce sufficient amount of oxygen for the complete  combustion of $C_2H_2$ which produces 11.2 L of $CO_2$ at STP after combustion is_________.<br/>$Ag_2CO_3 (s) \, \rightarrow\, 2Ag (s)\, +\, CO_2 (g)\, +\, \dfrac12 O_2 (g)$<br/>$C_2H_2\, +\, \dfrac52 O_2\, \rightarrow\, 2CO_2\, +\, H_2O$<br/>
Question 244 :
We know that balancing of a chemical equation is entirely based on the law of conservation of mass. However the concept of Principle of Atom Conservation (POAC) can also be related to law of conservation of a mass in a chemical reaction. So, POAC can also acts as a technique for balancing a chemical equation. For example, for a reaction $ABC_3 \rightarrow AB +C_2$ On applying POAC for A, B and C and relating the 3 equation we get : $\dfrac {n_{ABC_3}}{2}=\dfrac {n_{AB}}{2}=\dfrac {n_{C_2}}{3}$ (N= number of moles of X) Thus the coefficients of $ABC_3$, AB and $C_2$ in the balanced chemical equation will be 2,2 & 3 respectively and the balanced chemical equation can be represented as :$2ABC_3 \rightarrow 2AB +3C_2$Now answer the following question.<br/> <br/>If the weight ratio of C and $O_2$ present is 1:2 and both of the reactants completely cousumes and form CO and $CO_2$ and we will obtain a gaseous mixture of CO and $CO_2$ . What would be the weight ratio of CO and $CO_2$  in mixture?
Question 245 :
What is the minimum mass of ${ CaCO }_{ 3 }(s)$, below which it decomposes completely, required to established equilibrium in a $6.50\ litre$ container for the reaction:<br/>${ CaCO }_{ 3 }(s)\rightleftharpoons CaO(s)+{ CO }_{ 2 }(g);\space { K }_{ c }=0.005\ mole/litre$<br/>
Question 247 :
For the reaction of sodium with water, the balanced equation using the smallest whole numbers has which of the following coefficients?<br/>I. $1$<br/>II. $2$<br/>III. $3$<br/>Select the correct option.<br/>
Question 249 :
What mass of ammonium nitrate should be heated to produce 8.96 litres of steam? [Note : Relative molecular mass of $NH_4NO_3$ is 80]
Question 250 :
Which of the following chemical reaction is balanced as well as is combustion reaction?
Question 252 :
A quantity of $12\ g$ of magnesium is burnt completely in air $(O_{2}=20\%$ and $N_{2}=80\%$ by volume). Which of the following is/are correct statement(s) regarding this combustion?
Question 254 :
A mixture of propane and benzene is burst completely in excess of oxygen at $110^{o}C$. It result the production of equal volumes of $CO_{2}(g)$ and steam (measured under identical pressure and temperature). Which of the following is correct regarding the original mixture?
Question 255 :
A metal ($A$) on heating in nitrogen gas gives compound $B$. $B$ on treatment with ${H}_{2}O$ gives a colourless gas which when passed through $Cu{SO}_{4}$ solution gives a dark blue-violet coloured solution. $A$ and $B$ respectively, are :
Question 256 :
Consider the following statements.<br/><br/>1. If all the reactants are not taken in their stoichiometric ratio, then at least one reactant will be left behind.<br/><br/>2. 2 moles of $H_2(g)$ and 3 moles of $O_2 (g)$ produce 2 moles of water.<br/><br/>3. If equal weights of carbon and oxygen are taken to produce $CO_2$, then $O_2$ is limiting reagent.<br/><br/>The above statements 1, 2, 3 respectively are (T = True, F = False):
Question 257 :
The reaction, when balanced, $m, n, p$ and $q$ are respectively:<br/>$K_2Cr_2O_7+ \ m FeSO_4+n H_2SO_4\rightarrow Cr_2(SO_4)_3+pFe_2(SO_4)_3+K_2SO_4+qH_2O$ 
Question 258 :
The equation which is balanced and represents the correct product is:
Question 259 :
A quantity of 5.68 g of pure $ P_{4}O_{10} $ is dissolved completely in sufficient water and the solution is diluted to 250 ml. Which of the following statement (s) is/are correct?
Question 260 :
When an element of very low ionization potential reacts with an element of very high electron affinity, then :
Question 261 :
$Li$, $K$, $Ca$, $Na$, $Mg$, $Al$, $Zn$, $Fe$, $Pb$, $Cu$, $Hg$, $Ag$<br/>Which metal will displace hydrogen from acids but not water?
Question 262 :
On the basis of following features identify the correct option:<br/>I. This metal is not obtained in free state.<br/>II. This metal is obtained by electrolysis of their chlorides in molten state.
Question 265 :
The structure of glycine (amino acid) is $H_{2}N-CH_{2}COO^{-}$ ($z$ witter ion). Select the correct statement:-
Question 266 :
The complete loss of an electron of one atom to another atom with the consequent formation of electrostatic charges is said to be
Question 267 :
During electrolytic refining of copper.<br/>(a) Pure copper acts as anode.<br/>(b) Pure copper acts as cathode.<br/>(c) Impure copper acts as anode.<br/>(d) Impure copper acts as cathode.<br/>
Question 268 :
Galvanisation is a method of protecting iron from rusting, by coating with a thin layer of:<br/>
Question 274 :
Most of the metals which occurs in native state in nature:
Question 275 :
In case of formation of ionic compounds, the electronegativity difference between them is less than 1.7.<br/>
Question 276 :
Electrolysis is used in the extraction of metals from their ores.
Question 277 :
Coulomb's law is used to calculate the energy of an ion pair.
Question 278 :
Which of the following metals exist in their native state in nature?<br/>(i) Ca<br/>(ii) Au<br/>(iii) Zn<br/>(iv) Ag<br/>
Question 279 :
During the formation of sodium chloride, sodium transfers one electron to chlorine to attain the configuration of which noble gas?
Question 281 :
During the formation of ionic bond ________transfer takes place from one atom to the others.
Question 282 :
 Galvanizing is a process of coating iron with a metal to prevent it from rusting. The metal is :
Question 284 :
Assertion: Zinc is used in the galvanization of iron.
Reason: Its coating on iron articles increases their life by protecting them from rusting.
Question 285 :
An ore contains arsenic and antimony as impurities. How are they removed during the process of roasting?<br/>
Question 288 :
We have $CuSO_4$ solutions (blue) in two beakers A and B. In beaker A we add Ag pieces and in B we add Zn pieces. What will happen in A if :<br/>1. $Cu^{2+}$ is reduced to Cu<br/>2. no reaction.
Question 290 :
Which one of them is more ionic $LiCl$ or $NaCl$ ?
Question 292 :
What are the conditions for a species to act as a donor and an acceptor during dative bond formation?
Question 295 :
The process of protecting iron by coating with zinc is called:
Question 296 :
$2ZnS(s) + 3O_{2}(g) \xrightarrow {heat} 2ZnO(s) + 2SO_{2}(g)$ is an example of which type of reaction?
Question 297 :
A solid compound "A" consists of simple ions.<br/>Nature of the bond present in A will be:
Question 298 :
The bonds present in $\left( { N }_{ 2 }{ O }_{ 5 } \right) $ are:<br/>
Question 300 :
Separation of impurities from the extracted metals is known as __________.
Question 303 :
A magnesium ion has a net positive charge while the magnesium atom has __________. 
Question 304 :
Read the following statements and answer as true or false.<br/>Metals occur in nature only as free elements.<br/>
Question 305 :
The second most abundant metal present in the crust of the earth is :
Question 308 :
In electrolytic refining, which one is the anode and which is cathode?
Question 310 :
Extraction of metals from their ores by chemical methods requires the use of reducing agent.
Question 314 :
Which of the following pairs of elements form oxides of polyanions and polycations respectively:
Question 317 :
Which of the following pairs will form the most stable ionic bond?
Question 318 :
Zinc sulphate forms a colourless solution in water. Colour on adding copper  is :<br/>
Question 320 :
Assertion: An ionic solid is a good conductor of electricity.
Reason: An ionic solid is composed of positive and negative ions joined together by electrostatic forces.
Question 324 :
The process of converting hydrated alumina into anhydrous alumina is called
Question 325 :
An element with lowionization potential is most likely to form a covalent bond with an otherelement having a high electron affinity.
Question 326 :
Which pair in the following has maximum and minimum ionic character respectively?<br/>
Question 327 :
Choose the correct code regarding roasting process:<br/>(I) It is the process of heating ore in air to obtain the oxide.<br/>(II) It is an exothermic process.<br/>(III) It is used for hydrated oxide and oxy salt ore.<br/>(IV) It is used after the concentration of ore.<br/>
Question 328 :
An element with the atomic number $19$ will most likely combine chemically with the element whose atomic number is :
Question 330 :
Metals in the middle of the activity series are generally present as _______ in nature.
Question 331 :
Assertion: Stannous chloride gives grey precipitate with mercuric chloride, but stannic chloride does not do so.
Reason: Stannous chloride is a powerful oxidising agent which oxidises mercuric chloride to metallic mercury.
Question 335 :
When sodium reacts with cold water, then the product formed will be:
Question 338 :
Aluminium can be used as a reducing agent for extraction of metals that are:
Question 339 :
The type of bonds present in ${ PH }_{ 4 }I$ are:<br/>
Question 340 :
The salt prepared by the method of direct combination is ____________.
Question 341 :
In calcination, ore is heated strongly in the absence of air.
Question 346 :
The metals in the middle of activity series such as iron, zinc, led, copper, etc are moderately reactive. These are usually present as _______ in nature.<br/>
Question 349 :
Name a metal from the activity series which displaces hydrogen from steam?<br/>
Question 350 :
A metal carbonate on heating is converted to metal oxide and is reduced to 60% of its original weight. The equivalent weight of the metal is :
Question 351 :
What will be the colour of the blue cobalt chloride paper dipped in water?
Question 352 :
The density of non metals is _____ when compared with metals.<br/>
Question 353 :
Name one metal that will not react with cold water but will react with steam.
Question 355 :
A silvery-white metal $X$ reacts with water at room temperature to produce a water-soluble compound $Y$ and a colourless gas $Z$. The reaction is highly exothermic and the $Z$ catches fire immediately during the reaction. The solution of $Y$ in the water on reacting with a stoichiometric amount of dilute solution of hydrochloric acid gives a solution of $pH = 7.0$. <br/>The compounds $X,\ Y$ and $Z$ respectively are:<br/>
Question 356 :
Assertion: A cation of less size is more favorable for ionic bond formation.
Reason: If the size of the atoms is small, the nuclear pull on the electrons is more.
Question 357 :
$\displaystyle xFe+yH_{2}O\rightarrow zFe_{3}O_{4}+wH_{2}$<br>What are x, y, z and w respectively ?
Question 361 :
Assertion (A): In the electrolysis of aqueous NaCl,Na is preferentially discharged at the mercurycathode forming sodium amalgam.<br>Reason (R) : It is due to the fact that hydrogenhas a high over voltage at mercury cathode.<br>
Question 362 :
Which of the following process is used in the extractive metallurgy of magnesium ?
Question 363 :
Which of the following statement is incorrect about the extraction of lead from galena?<br>
Question 365 :
Which one of the following reactions will occur on heating $AgNO_3$?
Question 366 :
When a group IIA atom forms an ion, what charge does it have?
Question 367 :
Which one of the following metals will not reduce $ H_2 O? $
Question 369 :
Consider the following statements. Roasting is carried out to:<br/>(i) convert sulphide to oxide and sulphate.<br/>(ii) to remove impurities of $CuS$ and $FeS$ present in the ore of tin stone $(SnO_2)$ as $CuSO_4$ and $FeSO_4$.<br/>(iii) melt the ore.<br/>(iv) remove arsenic and sulphur impurities.<br/>Of these statements:<br/>
Question 372 :
Assertion: Ionic bonds are directional in nature whereas covalent bonds are non-directional.
Reason: According to orbital overlap concept, the formation of a covalent bond between two atoms results by pairing of electrons present in the valence shell having same spins.
Question 374 :
For purification of alumina, the modern processes most useful when (i) The impurity present is lot of iron oxides and (ii) the impurity present is a lot of silica, are
Question 375 :
Which of the following has a bond formed from the transfer of electrons?
Question 378 :
In self reduction process, the species which bring about the reduction is :<br/>
Question 379 :
Amongst $LiCl$, $ BeCl_2,\ MgCl_2 $ and $RbCl$ the compounds with greatest and least ionic character, respectively are:
Question 380 :
Which of the following is not a property of an ionic compound?
Question 381 :
In $Fe-$extraction, the roasting is adopted though the ore is no having any sulphide because:
Question 382 :
Mark the correct statements:<br/><br/>(i) mercury can be refined by the process of distillation.<br/><br/>(ii) In poling, the molten impure metal is stirred with green poles of wood.<br/><br/>(iii) In electrolyte refining of metals, impure metal is made as cathode and a thin strip of pure metal is made as anode.
Question 383 : <p>Some of the following metals are obtained by electrolysis of their fused salts.</p><p>$Al, Na, Cu, Ag, Mg, Ca$<br/></p><p>These metals are:</p>
Question 384 :
Which of the following family form negative ions in an ionic bond?
Question 386 :
Assertion: In smelting, roasted ore is heated with powdered coke in presence of a flux.
Reason: Oxides are reduced to metals by $C$ or $CO$. Impurities are removed as slag.
Question 387 :
In Down's process for the extraction of sodium, the melting point of $NaCl$ is lowered from $803^{0}C$ to $600^{0}C$.<br/><br/>Choose the correct statement(s) regarding this.<br/>a) It is done in order to avoid vapourisation of metallic sodium.<br/>b) It is done in order to avoid corrosive action of sodium and chlorine on the vessel at the high temperature.<br/>c) It is done by mixing sufficient amounts of $CaCl_2$.<br/>
Question 390 :
Roasting is carried out to :1) convert sulphide to oxide and sulphate. <br/>2) remove the water of hydration. <br/>3) melt the ore. <br/>4) remove arsenic and sulphur impurities.<br/>Choose the correct options.
Question 392 :
Statement 1: Powdered zinc reacts faster with acid than a larger piece of zinc.<br/>Statement 2: Powdered zinc has a greater surface area.
Question 393 :
Roasting of copper pyrite ores is for which of the following purpose?
Question 395 :
Which of the following sets of characteristics leads to the increase in solubility of ionic substances?
Question 396 :
ZnO in step (ii) can also be dissolved in NaOH forming :
Question 398 :
The element X reacting with chlorine forms a water soluble compound having high melting point. Element X is:
Question 399 :
Which set of compounds in the following pair of ionic compounds has the higher lattice energy?<br/>(I) $KCl$ or $MgO$<br/>(II) $LiF$ or $LiBr$<br/>(III) $MgF_2$ or $NaCl$<br/>
Question 401 :
$FeS + HCl \rightarrow A + B(g)$<br/><br/>Gas $B$ is passed into aqueous solution of $C$ to form $A$. Select correct statements based on the above facts.
Question 402 :
Select the correct reason for given statement 'Fluoride of $Al$ is ionic while chloride is covalent'.
Question 403 :
Which of the following equilibria would have the lowest value of $K_{p}$ at a common temperature?
Question 405 :
Among the following pairs of oxides, In which pair both are reduced by carbon?
Question 407 :
Solubility of $NaCl$, $Na_2SO_4$ and $Na_3PO_4$ in water in increasing order is :
Question 408 :
Sodium is made by the electrolysis of molten mixture of about $40\% \ NaCl$ and $60\%$ $CaCl_2$ because:
