Question

The rate of reaction depends only on the concentration of reactants or also on products?

Answer 1

Probably, in all the reactions you meet, the rate of reaction depends only on the concentration of reactants.

Explanation:

(a) Irreversible reactions

If the reaction is irreversible, say,

`"A + B → C + D"`

the rate depends only on the concentration of reactants.

It will be of the form

`"Rate" = k["A"]^m["B"]^n`

where `m` and `n` are numbers that must be determined experimentally.

These are probably the only types of reactions you will see in an introductory course.

(b) Complicated reactions

However, some reactions are complicated and have complicated rate laws.

For example, the reaction

`"H"_2 + "Br"_2 → "2HBr"`

has the complicated rate law

`"rate" = (["H"_2]["Br"_2]^(1/2))/(1+ k^"'"(["HBr"])/(["Br"_2])`

Please don't memorize this equation.

I mention it only to show that there are reactions in which the concentrations of products can be involved in the rate law.