Question

The rate constant of a first order reaction whose half-life is 480 seconds, is ____________.

Options

• 2.88 × 10⁻³ s⁻¹

• 1.44 × 10⁻³ s⁻¹

• 1.44 s⁻¹

• 0.72 × 10⁻³ s⁻¹

Answer 1

The rate constant of a first order reaction whose half-life is 480 seconds, is 1.44 × 10⁻³ s⁻¹.

Explanation:

For a first order reaction, the expression relating rate constant (k) and half-life `("t"_(1/2))` is k = `0.693/"t"_(1/2)`.

Substituting `"t"_(1/2)` = 480 s in the above expression,

k = `0.693/"t"_(1/2) = 0.693/(480  "s")`

= 1.44 × 10⁻³ s⁻¹