Units of rate constnat is the same for the elementary reactions :
Reaction (1) ` A + B + C to` products,
Reaction (2) , `A + 2B to` products,
Reaction (3), `3A to ` products. Substantiate.

Explanation

`A+B+Cto` products , rate = k [A] [B] [C]
`A+2Bto` products , rate = `"k [A] "["2B"]^(2)`
`3Ato` products , rate `=k[A]^(3)`
Since the number of concentration terms is the same for all the rate laws, the units of rate constant are also same. The units of rate constant of any of these reactions are `L^(2)" mol"^(-2)s^(-1)`.