Question

The rate constant for a second order reaction is 8 x 10^-5 M^-5 min^-1 . How long will it take a 1 M solution to be reduced to 0.5 M in reactant?(a) 8.665 x 10^3 min (b) 8 x 10^-5 min (c) 1.25 x 10^4 min (d) 4 x 10^-5 min​

Answer 1

Given:

k = 8 × 10⁻⁵ M⁻¹ min⁻¹

[R]₀ = 1 M

[R] = 0.5 M

To Find:

The time required to reach 0.5 M from 1 M concentration.

Calculation:

- Since [R] = [R]₀/2

⇒ It is the half-life time period.

- The half-life period of a second order reaction can be given as:

T1/2 = 1/k[R]₀

⇒ T1/2 = 1/(8 × 10⁻⁵ × 1)

⇒ T1/2 = 0.125 × 10⁵

⇒ T1/2 = 1.25 × 10⁴ min

- So, the correct answer is option (c) 1.25 × 10⁴ min.