set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

Because of impurities the boiling point of a liquid

a) Decreases

b) Remains constant

c) Increases

d) They are not related

Question : 2

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

Question : 3

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 : 4

Which of the following group of elements belongs to alkali metals?

a) 37, 19, 3, 55

b) 9, 17, 35, 53

c) 1, 12, 30, 4, 62

d) 12, 20, 56, 88

Question : 5

If the valene shell electronic configuration for an element is $ns^2np^5$, this element will belong to the group of –

a) inert metals

b) noble gases

c) alkali metals

d) halogens

Question : 6

Which one of the following is a diagonally related pair?

a) Na, Mg

b) B, Si

c) H, Be

d) K, Ca