Question 1 :
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Question 2 :
Balance the following chemical equations:
$NaOH + H_{2}SO_{4} \rightarrow Na_{2}SO_{4} + H_{2}O$
Question 3 :
Write the balanced chemical equations for the following reactions:
Calcium hydroxide + Carbon dioxide $\rightarrow$ Calcium carbonate + Water
Question 4 :
Balance the following chemical equations:
$HNO_{3} + Ca(OH)_{2} \rightarrow Ca(NO_{3})_{2} + H_{2}O$
Question 5 :
Write the balanced chemical equation for the following and identify the type of reaction in each case:
Hydrogen (g) + Chlorine (g) $\rightarrow$ Hydrogen chloride (g)
Question 6 :
What is used to measure strength of an acid or a base?
Question 8 :
Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain .
Question 9 :
Which gas is used in the manufacturing of ammonia in fertilisers?
Question 11 :
What are the compounds who have similar molecular formula but different structure called?
Question 12 :
Would you be able to check if water is hard by using a detergent?
Question 13 :
Which of the options explain the atomic arrangement in diamond ?
Question 15 :
Why is the conversion of ethanol to ethanoic acid an oxidation reaction?
Question 16 :
How is a voltmeter connected in the circuit to measure the potential difference between two points?
Question 18 :
Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source?
Question 19 :
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. What is the value of the resistance of the resistor?
Question 21 :
A magnetic compass shows a deflection when placed near a current carrying wire. How will the deflection of the compass get affected if the current in the wire is increased ?
Question 23 :
For a current in a long straight solenoid N- and S-poles are created at the two ends. Among the following statements, the incorrect statement is
Question 26 :
Food cans are coated with tin and not with zinc because
Question 27 :
Food cans are coated with tin and not with zinc because
Question 30 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b19c7e273b230584979aeb.JPG' />
Samples of four metals A, B, C and D were taken and added to the different solution one by one. The results obtained have been tabulated above. Use the given table to answer the following questions about metals A, B, C and D.
Arrange the metals in decreasing order of reactivity.
Question 33 :
Gobar-gas is produced when crops, vegetable wastes etc., decompose in the absence of oxygen. TRUE or FALSE ?
Question 34 :
Which is the major direct environmental consequences of using fossil fuels?
Question 35 :
What is the role of a plane mirror in a solar cooker?
Question 36 :
Use Mendeleev's periodic table to predict the formulae for the oxides of the elements 'Ba'.
Question 37 :
Use Mendeleev's periodic table to predict the formulae for the oxides of the elements 'C'.
Question 38 :
Use Mendeleev's periodic table to predict the formulae for the oxides of the elements 'Si'.
Question 39 :
Use Mendeleev's periodic table to predict the formulae for the oxides of the elements 'Si'.
Question 41 :
Which of the following salts does not contain water of crystallisation?
Question 42 :
Fill in the blank: Potassium sulphate ($K_2SO_4$) is formed using _________(base) and _______(acid)
Question 43 :
Which of the following is the chemical formula for Slaked lime.
Question 44 :
State True or False: When HCl (g) is passed through water then it does not ionise in the solution as it is a covalent compound.
Question 45 :
Name the acid present in ant sting and give its chemical formula.
Question 46 :
Where will the image form by a concave mirror, when an object is placed a little beyond centre of curvature of the mirror.
Question 47 :
A child is standing in front of a magic mirror. She finds the image of her head bigger, the middle portion of her body of the same size and that of the legs smaller. The following is the order of combinations for the magic mirror from the top.
Question 48 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b19ced273b230584979b6c.PNG' />
<img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61cc185478c526e972caea2a.PNG' />
In the above images, the first image is the ray of light incident on a concave mirror and the second image is the complete path of the ray. Is the second image correct depiction of the path?
Question 49 :
Size of image of an object by a mirror having a focal length of 20 cm is observed to be reduced to 1/3rd of its size. What is the nature of the image?
Question 50 :
Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?
Question 51 :
What is the balanced chemical equation for Zinc carbonate(s) → Zinc oxide (s) + Carbon dioxide (g) ?
Question 52 :
What is the balanced chemical equations when barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate?
Question 53 :
A solution of a substance X' is used for white washing. Name the substance 'X'.
Question 54 :
Balance the chemical equation:- $BaCl_2 + H_2SO_4 → BaSO_4 + HCl$.
Question 55 :
$Fe_2O_3$ + 2Al → $Al_2O_3$ + 2Fe. The above reaction is an example of a
