Question

The rate constant of a first order reaction is 3 × 10⁻⁶ per s. If the initial concentration is 0.10 mol dm⁻³, the initial rate of reaction is ____________.

Options

• 3 × 10⁻⁵ mol dm⁻³ s⁻¹

• 3 × 10⁻⁶ mol dm⁻³ s⁻¹

• 3 × 10⁻⁷ mol dm⁻³ s⁻¹

• 3 × 10⁻⁸ mol dm⁻³ s⁻¹

Answer 1

The rate constant of a first order reaction is 3 × 10⁻⁶ per s. If the initial concentration is 0.10 mol dm⁻³, the initial rate of reaction is 3 × 10⁻⁷ mol dm⁻³ s⁻¹.

Explanation:

Order = 1

Rate constant k = 3 × 10⁻⁶ s⁻¹ ............(i)

Initial concentration = [A]₀

= 0.10 mol dm⁻³ ....(ii)

The rate law is, Initial rate = k[A]₀ ......(iii)

Substituting the values of k from (i) and [A]₀ from (ii) in the expression (iii),

Initial rate = 3 × 10⁻⁶ s⁻¹ × 0.10 mol dm⁻³

= 3 × 10⁻⁷ mol dm⁻³ s⁻¹