Question 5 : <div>The oxidation state of the underlined element in the given compound is:<br/></div>$\underline{C_{12}}H_{22}O_{11}$
Question 6 :
Oxidation number of $P$ in $PO^{3-}_4$, of $S$ in $SO^{2-}_4$ and that of $Cr$ in $Cr_2O^{2-}_7$ are respectively:<br/>
Question 8 : <div>Which of the reactants act as oxidant or reductant if any:<br/></div><div><br/></div>$[Ag(NH_3)_2]^++ 2H^+ \rightarrow Ag^+ + 2NH^+_4$
Question 11 :
Which of the following is not a rule for calculating oxidation number ?<br><br>
Question 14 :
In which of the following compounds is the oxidation state of $C$ highest?
Question 15 :
How many moles of electrons are involved in the reduction of one mole of $ {MnO}^{-}_4$ ion in an alkaline medium to $ {MnO}^{-}_3$?
Question 16 :
In a reaction, $4$ moles of electrons are transferred to $1$ mole of ${HNO}_{3}$. The possible product obtained due to reduction is :
Question 17 :
In the redox reaction, $Na + 1/2 H_2 \rightarrow NaH$, choose the correct statement.
Question 21 :
When methane is burnt in oxygen to produce $CO_2$ and $H_2O$, the oxidation number changes by____________.
Question 23 :
In ${ Ni(CO) }_{ 4 }$, the oxidation state of Ni is:
Question 26 :
The oxidation state of the underlined element in the given compound is:<br/>$Na_2[\ \underline{Fe}(CN)_5NO\ ]$
Question 28 : Select the strongest oxidant oxoanion and weakest oxidant oxanion among the following:<div>$ VO^{3-}_4, CrO^{2-}_4, MnO^{2-}_4, FeO^{2-}_4$</div>
Question 29 :
In which of the following compounds the oxidation number of carbon is not zero?
Question 30 : The oxidation state of $Mn$ in $K_2MnO_4$ is same as that in $MnO_2$.<div>Is the above statement true?</div>
Question 31 :
Oxidation state of phosphorous in $\displaystyle \ { P } { O }_{ 4 }^{ 3- }$ is:<br/>
Question 32 :
What is the oxidation state of copper in the compound, $YBa_2Cu_3O_7$ which shows super conductivity? Assume that the rare earth element, yttrium is in its usual $+3$ oxidation state.
Question 37 :
Assertion: Nitrous acid $(HNO_{2})$ may act as an oxidising as well as reducing agent.
Reason: The oxidation number of nitrogen remains same in all the compounds.
Question 38 : <div>Following reaction is:</div>$Mn{ O }_{ 4 }^{ - }(aq)\longrightarrow Mn{ O }_{ 4 }^{ 2- }(aq)$
Question 40 :
When $PbS$ is treated with warm dilute ${HNO}_{3}$, the products are most likely to be :<br/>
Question 41 : <div>True statements for the chemical reaction of the formation of lithium oxide is:<br/>$4Li(s) + O_2(g)\rightarrow 2Li_2O(s)$<br/></div>
Question 42 :
An element in its free state will have the oxidation number:<br/>
Question 43 :
Determine the oxidation state of the underlined element in ${ Rb }_{ 4 }Na\left[ H\underline { { V }_{ 10 } } { O }_{ 28 } \right] $.<br/>
Question 46 :
Various oxidation states of few elements are mentioned, Which of the options is not correctly matched?
Question 47 :
When an oxidising agent reacts, it consumes electrons. In the following changes, which one of the oxidising agents has consumed maximum number of electrons per mole?
Question 51 : The reaction between magnesium and carbon dioxide is shown in the equation.<br/>$2Mg + CO_{2}\rightarrow 2MgO + C$<br/><br/><div>Which statement describes what happens in this reaction?</div>
Question 53 :
The compound of nitrogen in which nitrogen carries a fractional oxidation state is:<br/>
Question 57 :
Chlorine change oxidation number.<br/>$2Na\left( s \right) +{ Cl }_{ 2 }\left( g \right) \longrightarrow 2NaCl\left( s \right)$
Question 58 : <div>Find the oxidation number of elements in each case .<br/></div><div><br/></div>$O$ in  $ O_2,O_3, OF_2$ and $BaO_2$.
Question 60 :
Assertion: The reaction between $N{ H }_{ 3 }$ and $Mn{ O }_{ 4 }^{ \ominus }$ occurs in an acidic medium.<br>$N{ H }_{ 3 }+Mn{ O }_{ 4 }^{ \ominus }\longrightarrow Mn{ O }_{ 2 }+N{ O }_{ 2 }$
Reason: $Mn{ O }_{ 4 }^{ \ominus }$ is reduced to $Mn{ O }_{ 2 }$ in acidic medium.
Question 62 :
If $4$ mol of $Br_2$ undergo a loss and gain of a total of $6$ mol electrons to form two new oxidation state of $Br_2$. How many moles of $Br_2$ acts as reductant?
Question 63 :
During oxidation of ferrous sulphate using mixture of dil. $H_2SO_4$ and potassium dichromate; oxidation state of chromium changes from: <br/>
Question 64 :
When potassium dichromate, ${K}_{2}{Cr}_{2}{O}_{7}$ is converted into ${K}_{2}Cr{O}_{4}$, the change in oxidation number of chromium is :
Question 65 :
A compound contains atoms $X,\ Y$ and $Z$. The oxidation number of $X$ is +2, $Y$ is +5 and $Z$ is -2.<br>The possible formula of the compound is:
Question 67 : <div>Find the oxidation number of nitrogen in each case :<br/></div><div><br/></div>$ N$ in $NH_3, NH_2OH, NaN_3$ and $NH_4NO_2$.
Question 68 :
A compound contains three elements $X, Y$ and $Z$. The oxidation number of $X, Y$ and $Z$ are $+3, +5$ and $-2$ respectively. The possible formula of the compound is:
Question 69 :
The oxidation number of underlined element in  $\displaystyle Na_{2}\left [ \underline{Fe}\left ( CN \right )_{5}NO^{+} \right ]$ compound is :
Question 70 :
Identify the case (s) where there is change is oxidation number.
Question 71 :
Assertion: $HN{ O }_{ 3 }$ acts only as an oxidising agent while $HN{ O }_{ 2 }$ acts both as an oxidising agent and a reducing agent.
Reason: The oxidation number of $N$ in $HN{ O }_{ 3 }$ is maximum.
Question 72 :
In which of the following compounds, nitrogen exhibits highest oxidation state?
Question 73 :
In the reaction $H_2O_2 + Na_2CO_3 \rightarrow Na_2O_2 + CO_2 + H_2O$, the substance undergoing oxidation is:
Question 74 :
$Cu(s) +NO_{3}^{-}(aq) +H^+(aq) \rightarrow Cu^{2+}(aq) +NO_2(g) +H_2O(l)$<br/>Select the correct statement regarding above reaction.
Question 76 :
When a piece of sodium metal is dropped in water, hydrogen gas evolved because:
