Question

For a first order reaction, \[\ce{A -> B}\], if [A] = 1 M and rate is 4 × 10⁻² M s⁻¹. What is the rate constant of the reaction?

Options

• 4 × 10⁻² s⁻¹

• 0.4 × 10⁻² s⁻¹

• 2 × 10⁻² s⁻¹

• 2.5 × 10⁻⁵ s⁻¹

Answer 1

4 × 10⁻² s⁻¹

Explanation:

For a first order reaction,

\[\ce{A -> B}\]

Rate = k [A]

k = `"Rate"/(["A"])`

= `(4 xx 10^-2)/1`

= 4 × 10⁻² s⁻¹