Is first order in bro3⎻ , second order in br⎻, and zero order in h+. by what factor will the reaction rate change if the concentration of bro3⎻ is doubled, the concentration of br⎻ is halved, and the concentration of h+ is tripled ?

For a general reaction,

General expression for rate law  will be:

Here, r is rate of the reaction, k is rate constant, a is order with respect to reactant A and b is order with respect to reactant B.

The reaction is first order with respect to , second order with respect to and zero order with respect to .

According to above information, expression for rate law will be:

Or,

...... (1)

...... (2)

Dividing (2) by (1)

Or,

Thus, rate of the reaction also get doubled.

Or,

...... (3)

Dividing (3) by (1)

Or,

Thus, rate of reaction becomes 1/4th of the initial rate.

Since, the rate expression does not have concentration of , it is independent of it. Thus, any change in the concentration will not affect the rate of reaction and rate of reaction remains the same as in equation (1).