JEE Main, NEET MCQs Set 8

Sr. No.

Question

Answer

1.

During the formation of a chemical bond

(A) energy decreases

(B) energy increases

(C) energy of the system does not change

(D) electron-electron repulsion becomes more than the nucleus-electron attraction

Answer: (A)

2.

E₁, E₂ and E₃ are the emf values of the three galvanic cells respectively.

a) Zn | || |Cu

b) Zn | || |Cu

c) Zn | || |Cu

Which one of the following is true?

(A) E₃ > E₂ > E₁

(B) E₂ > E₃> E₁

(C) E₁ > E₃> E₂

(D) E₁ > E₂> E₃

Answer: (A)

3.

Ellingham diagram represents a graph of

(A) DG Vs T

(B) DG⁰ Vs T

(C) DS Vs P

(D) DG Vs P

Answer: (B)

4.

Enthalpy change for the reaction, 4H_(g) → 2H_2(g) is –869.6 kJ. The dissociation energy of H – H bond is

(A) +217.4 kJ

(B) –434.8 kJ

(C) –869.6 kJ

(D) +434.8 kJ

Answer: (D)

5.

Enthalpy of vapourization of benzene is +35.3 kJ mol^–1 at its boiling point of 80°C.

The entropy change in the transition of the vapour to liquid at its boiling point

[in JK^–1 mol^–1] is ______.

(A) –100

(B) –441

(C) +100

(D) +441

Answer: (A)

6.

Entropy of the universe is

(A) continuously increasing

(B) continuously decreasing

(C) zero

(D) constant

Answer: (A)

7.

Excess of carbon dioxide is passed through 50 ml of 0.5 M calcium hydroxide solution.  After the completion of the reaction, the solution was evaporated to dryness. The solid calcium carbonate was completely neutralised with 0.1 N Hydrochloric acid. The volume of Hydrochloric acid required is (At. mass of calcium = 40)

(A) 500 cm³

(B) 400 cm³

(C) 300 cm³

(D) 200 cm³

Answer: (A)

8.

Excess of PCl₅ reacts with conc. H₂SO₄ giving

(A) chlorosulphonic acid

(B) thionyl chloride

(C) sulphuryl chloride

(D) sulphurous acid

Answer: (C)

9.

For a chemical reaction A → B, the rate of the reaction is 2 × 10^–3 mol dm^–3 s^–1, when the initial concentration is 0.05 mol dm^–3. The rate of the same reaction is 1.6 × 10^–2 mol dm^–3 s^–1when the initial concentration is 0.1 mol dm^–3. The order of the reaction is

(A) 3

(B) 1

(C) 2

(D) 0

Answer: (A)

10.

For a stable molecule the value of bond order must be

(A) negative

(B) positive

(C) zero

(D) there is no relationship between stability and bond order.

Answer: (B)