CBSE Class 10 Science Acids bases and salts Sure Shot Questions Set 04

Question. When sodium chloride reacts with sulphuric acid, a gas is evolved which gives dense white fumes with ammonia. Which gas is evolved?
(a) \( HCl \)
(b) \( NH_4Cl \)
(c) \( NH_4OH \)
(d) \( (NH_4)_2SO_4 \)
Answer: (a) \( HCl \)

Question. For dilution of concentrated acid we should add
(a) water into concentrated acid
(b) concentrated acid into water
(c) first water into acid and then more acid
(d) Both (a) and (b) are correct
Answer: (b) concentrated acid into water

Question. A solution turns blue litmus red. The pH of the solution is probably
(a) 8
(b) 10
(c) 12
(d) 6
Answer: (d) 6

Question. When bitten by an ant, the sting causes irritation due to the presence of
(a) a base in the sting
(b) formic acid in the sting
(c) poisonous chemicals
(d) Both (a) and (b)
Answer: (b) formic acid in the sting

Question. Which of the following is incorrectly matched ?
(a) Tomato – tartaric acid
(b) Ant sting – citric acid
(c) Citrus fruit – citric acid
(d) Curd – lactic acid
Answer: (b) Ant sting – citric acid

Question. Two solution A and B were found to have pH value of 6 and 8 respectively. The inference which can be drawn is that
(a) the acid strength of the solution B is higher than that of A
(b) A is an acid while B is a base
(c) Both are acidic solutions
(d) Both are basic solutions
Answer: (b) A is an acid while B is a base

Question. pH + pOH equals
(a) zero
(b) fourteen
(c) a negative number
(d) infinity
Answer: (b) fourteen

Question. The acid used in making of vinegar is
(a) formic acid
(b) acetic acid
(c) sulphuric acid
(d) nitric acid
Answer: (b) acetic acid

Question. Antacids contain
(a) weak base
(b) weak acid
(c) strong base
(d) strong acid
Answer: (a) weak base

Question. The equation between an acid and a base is \( XOH + HY \to XY + H_2O \). Which of the following is the cation part of salt ?
(a) X
(b) OH
(c) H
(d) Y
Answer: (a) X

Question. To prevent tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is
(a) acidic
(b) neutral
(c) basic
(d) corrosive
Answer: (c) basic

Question. Which of the following compounds is neutral to litmus ?
(a) \( NaNO_3 \)
(b) \( CuSO_4 \cdot 5H_2O \)
(c) \( NaHCO_3 \)
(d) \( Ca(OH)_2 \)
Answer: (a) \( NaNO_3 \)

Question. On electrolysis of brine solution, the products formed are
(a) sodium and chlorine
(b) hydrogen, chlorine and oxygen
(c) hydrogen, chlorine and sodium hydroxide
(d) sodium hydroxide, chlorine and oxygen
Answer: (c) hydrogen, chlorine and sodium hydroxide

Question. Bleaching powder gives smell of chlorine because it -
(a) is unstable
(b) gives chlorine on exposure to atmosphere
(c) is a mixture of chlorine and slaked lime
(d) contains excess of chlorine
Answer: (b) gives chlorine on exposure to atmosphere

Question. Chemical formula of baking soda is
(a) \( MgSO_4 \)
(b) \( Na_2CO_3 \)
(c) \( NaHCO_3 \)
(d) \( MgCO_3 \)
Answer: (c) \( NaHCO_3 \)

Question. Soda-acid fire extinguisher extinguishes the fire by
(a) cutting the supply of air
(b) removing the combustible substance
(c) raising the ignition temperature
(d) None of the options
Answer: (a) cutting the supply of air

Question. Plaster of Paris is obtained
(a) by adding water to calcium sulphate
(b) by adding sulphuric acid to calcium hydroxide
(c) by heating gypsum to a very high temperature
(d) by cooling gypsum
Answer: (c) by heating gypsum to a very high temperature

Question. The difference of water molecules in gypsum and Plaster of Paris is
(a) 5/2
(b) 2
(c) 1/2
(d) 3/2
Answer: (d) 3/2

Question. Plaster of Paris on mixing with water sets to form
(a) \( CaSO_4 \cdot H_2O \)
(b) \( CaSO_4 \cdot 1\frac{1}{2} H_2O \)
(c) \( CaSO_4 \cdot 2H_2O \)
(d) \( CaSO_4 \cdot 2\frac{1}{2} H_2O \)
Answer: (c) \( CaSO_4 \cdot 2H_2O \)

Question. Plaster of Paris hardens by
(a) giving off \( CO_2 \)
(b) changing into \( CaCO_3 \)
(c) combining with water
(d) giving out water
Answer: (c) combining with water