JEE Main, NEET MCQs Set 19

Sr. No.

Question

Answer

1.

The d-electron configurations of Cr^2+, Mn2+, Fe²⁺ and Co²⁺are d⁴, d⁵, d⁶ and d⁷ respectively. Which one of the following will exhibit minimum paramagnetic behaviour?

(A) [Cr(H₂O)₆]²⁺

(B) [Mn(H₂O)₆]²⁺

(C) [Fe(H₂O)₆]²⁺

(D) [Co(H₂O)₆]²⁺

(At. nos. Cr = 24, Mn = 25, Fe = 26, Co = 27)

Answer: (D)

2.

The electrode potentials for andare + 0.15 V and + 0.50 V respectively. The value of   will be

(A) 0.150 V

(B) 0.500 V

(C) 0.325 V

(D) 0.650 V

Answer: (C)

3.

The electronic configuration of Cr³⁺ is

(A) [Ar]3d⁵4s¹

(B) [Ar]3d²4s¹

(C) [Ar]3d³4s⁰

(D) [Ar]3d⁴4s²

Answer: (C)

4.

The electrophile involved in the sulphonation of Benzene is

(A)

(B) so₃

(C)

(D)

Answer: (B)

5.

The empirical formula of a nonelectrolyte is C₁H₂O₁. A solution containing 6 g of the compound exerts the same osmotic pressure as that of 0.05 M glucose solution at the same temperature. The molecular formula of the compound is ______.

(A) C₃H₆O₃

(B) C₂H₄O₂

(C) C₄H₈O₄

(D) C5H₁₀O₅

Answer: (C)

6.

The energies E₁ and E₂ of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths i.e. and will be

(A) =

(B) =

(C) = 2

(D) = 4

Answer: (C)

7.

The enthalpy of formation of NH₃ is –46 kJ mo1^–1. The enthalpy change for the reaction :

2NH₃(g) → N₂(g) + 3H₂(g) is

(A) +92kJ

(B) +46 kJ

(C) +184 kJ

(D) +23 kJ

Answer: (A)

8.

The following data is obtained during the first order thermal decomposition of 2A_(g) → B_(g) + C_(s) , at constant volume and temperature.

The rate constant in min^–1 is ______.

(A) 6.93

(B) 0.0693

(C) 69.3

(D) 0.00693

Answer: (B)

9.

The freezing point depression constant for water is –1.86°Cm^–1. If 5.00 g Na₂SO₄ is dissolved in 45.0 g H₂O, the freezing point is changed by –3.82°C. Calculate the van’t Hoff factor for Na₂SO₄

(A) 0.381

(B) 2.05

(C) 2.63

(D) 3.11

Answer: (C)

10.

The function of Fe(OH)₃ in the contact process is

(A) to remove moisture

(B) to remove dust particles

(C) to remove arsenic impurity

(D) to detect colloidal impurity

Answer: (C)