set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

Which is not true about noble gases?

a) They exist in atomic form

b) They are radioactive in nature

c) They are non-metallic in nature

d) Xenon is the most reactive among them

Question : 2

Consider the following statements :

1. The molecules in a gas are in constant motion.
2. Gases have the same pressure throughout the entire atmosphere.
3. Gas molecules are always evenly distributed in the atmosphere.

a) 1 only

b) 1 and 2

c) 2 and 3

d) 2 only

Question : 3

Which one of the following is most electropositive element?

a) Calcium

b) Aluminium

c) Sodium

d) Silicon

Question : 4

Consider the following statements :

1. Living beings carry out their metabolic activities with in an optimal pH range.
2. There are a variety of strengths when you study acids and base.

a) 1 and 2 both

b) 1 only

c) 2 only

d) None

Question : 5

Which of the following statements about pH and $H^+$ ion concentration are incorrect?

1. Addition of one drop of concentrated HCl in NH₄OH solution decreases pH of the solution.
2. A solution of the mixture of one equivalent of each of CH₃COOH and NaOH has a pH of 7
3. pH of pure neutral water is not zero
4. A cold and concentrated H₂SO₄ has lower $H^+$ ion concentration than a dilute solution of H₂SO₄

a) 1, 2 and 4

b) 1, 2 and 3

c) 1, 3 and 4

d) 2, 3 and 4

Question : 6

Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively.
It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas, in the case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is (are) correct?

1. In beakers A and B, an exothermic process has occurred.
2. In beakers A and B, an endothermic process has occurred.
3. In beaker C exothermic process has occurred.
4. In beaker C endothermic process has occurred.

a) 1 and 4

b) 1 only

c) 2 only

d) 2 and 3