NEET 2025 Prep Test

Question 1

1. Specific conductance of 0.1 M nitric acid is 6.3 × 10⁻² ohm⁻¹ cm⁻¹. The molar conductance of the solution is:
   (a) 630 ohm⁻¹ cm² mol⁻¹
   (b) 315 ohm⁻¹ cm² mol⁻¹
   (c) 6.300 ohm⁻¹ cm² mol⁻¹
   (d) 63.0 ohm⁻¹ cm² mol⁻¹

Answer 1

1. (a): κ = 6.3 × 10⁻² ohm⁻¹ cm⁻¹, C = 0.1 M
   Λₘ = κ × 1000 / C = 6.3 × 10⁻² × 1000 / 0.1
   = 630 ohm⁻¹ cm² mol⁻¹

Question 2

2. If the rate of a reaction at 50°C is 2.6 × 10⁻³ mol L⁻¹ s⁻¹, then what will the rate of reaction be at 80°C?
   (Given that the temperature coefficient is 3.) (a) 7.02 × 10⁻²
   (b) 7.025 × 10⁻³
   (c) 7.8 × 10⁻³
   (d) None of these

Answer 2

2. (a): n = (80 - 50) / 10 = 3; rₙₑw / rₒₗd = (3)ⁿ
   New rate = 2.6 × 10⁻³ × 3³ = 70.2 × 10⁻³
   = 7.02 × 10⁻² mol L⁻¹ s⁻¹

Question 3

0.2 g of acetic acid dimerizes when dissolved in 20 g of benzene, decreasing the freezing point by 0.45°C.
The degree of association of acetic acid in benzene is:
(Given: Kf (benzene) = 5.12 K kg mol⁻¹)
(a) 45.9%
(b) 94.6%
(c) 69.4%
(d) 54.9%