1 - Which of the following is not physical change?
A. Boiling of water to give water vapour
B. Melting of ice to give water
C. Dissolution of salt in water
D. Combustion of Liquefied Petroleum Gas (LPG)
Answer - (D) - Combustion of Liquefied Petroleum Gas (LPG)
2 - Which of the following is true for an unbalanced chemical equation?
A. Number of atoms is equal on both sides of the equation
B. Number of atoms is less on the left side of the equation
C. Number of atoms is more on the right side of the equation
D. Both b and c
Answer - (D) - Both b and c
3 - Which option denotes a double displacement reaction?
A. A + B + C
B. A + B → C
C. AC + BD → AD + BC
D. AC + B → AB + C
Answer - (C) - AC + BD → AD + BC
4 - Which of the following is Not True with respect to the neutralisation reaction?
A. Salt is formed
B. Reaction occurs between an acid and a base.
C. Reactive element displaces less reactive element.
D. Reactants are in gaseous state.
Answer - (D) - Reactants are in gaseous state.
5 - Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is?
A. 1 : 1
B. 2 : 1
C. 4 : 1
D. 1 : 2
Answer - (B) - 2 : 1
6 - Combustion reactions are always?
C. Sometimes exothermic
D. Both a and b
Answer - (A) - Exothermic
7 - Which one of the following processes involve chemical reactions?
A. Storing of oxygen gas under pressure in a gas cylinder
B. Liquefaction of air
C. Keeping petrol in a China dish in the open
D. Heating copper wire in presence of air at high temperature
Answer - (D) - Heating copper wire in presence of air at high temperature
8 - An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?
A. Baking powder
C. Ammonium hydroxide solution
D. Hydrochloric acid
Answer - (D) - Hydrochloric acid
9 - The pH of a solution is 7. How can you increase its pH?
A. By adding a small amount of acid
B. By adding a small amount of base.
C. By adding a small amount of salt.
D. By passing carbon dioxide gas through it.
Answer - (B) - By adding a small amount of base.
10 - Sodium carbonate is a basic salt because it is a salt of?
A. strong acid and strong base
B. weak acid and weak base
C. strong acid and weak base
D. weak acid and strong base
Answer - (D) - weak acid and strong base
11 - Which of the following gives the correct increasing order of acidic strength?
A. Water < Acetic acid < Hydrochloric acid
B. Water < Hydrochloric acid < Acetic acid
C. Acetic acid < Water < Hydrochloric acid
D. Hydrochloric acid < Water < Acetic acid
Answer - (A) - Water < Acetic acid < Hydrochloric acid
12 - If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?
A. Wash the hand with saline solution.
B. Wash the hand immediately with plenty of water and apply a paste of sodium hydrogencarbonate.
C. After washing with plenty of water and apply solution of sodium hydroxide on the hand
D. Neutralise the acid with a strong alkali.
Answer - (B) - Wash the hand immediately with plenty of water and apply a paste of sodium hydrogencarbonate.
13 - Farmers neutralize the effect of acidity of the soil by adding?
A. slaked lime
C. caustic soda
D. baking soda
Answer - (A) - slaked lime
14 - A solution has turned the color of red litmus paper to blue. The pH of the solution is approximately?
Answer - (D) - 10
15 - Which one of the following can be used as an acid-base indicator by a visually impaired student?
C. Vanilla essence
D. Petunia leaves
Answer - (C) - Vanilla essence