Question

The activation energy of a reaction is zero. Its rate constant at 280 K is 1.6 × 10^-6 s^-1, the rate constant at 300 K is ______.

Options

• 3.2 × 10^-6 s^-1

• zero

• 1.6 × 10^-6 s^-1

• 1.6 × 10^-5 s^-1

Answer 1

The activation energy of a reaction is zero. Its rate constant at 280 K is 1.6 × 10^-6 s^-1, the rate constant at 300 K is 1.6 × 10^-6 s^-1.

Explanation:

Arrhenius equation is given as:

`log "k"_2/"k"_1 = "E"_"a"/(2.303"R") [1/"T"_1 - 1/"T"_2]`

Given,

Activation energy of a reaction, E_A = 0

Rate constant, k₁ = 1.6 × 10^-6 s^-1 

Temperature, T₁ = 280 K, T₂ = 300 K

According to Arrhenius equation

`log  "k"_2/(1.6 xx 10^-6) = 0/(2.303 "R") [1/280 - 1/300]`

`log "k"_2/(1.6 xx 10^-6)` = 0

`"k"_2/(1.6 xx 10^-6)` = antilog 0

`"k"_2/(1.6 xx 10^-6)` = 1

∴ k₂ = 1.6 × 10^-6 s^-1