Question

State the order of reaction whose rate constant possess the following unit: 

atm⁻² s⁻¹

Answer 1

To determine the order of the reaction from the units of the rate constant,

Units of k = (unit of concentration)¹⁻ⁿ ⋅ time⁻¹

Here, the concentration is given in atm, so:

Units of k = atm¹⁻ⁿ ⋅ s⁻¹

We are told:

Units of k = atm⁻² ⋅ s⁻¹

Equating powers of atm:

1 n = −2

n = 3

∴ The reaction is third order.