Kinetics - rate of reaction

Question

The chromium(III) species reacts with hydrogen peroxide in aqueous solution to form the chromate ion:

2CrO2- 3 H2O2 2OH- 2CrO42- 4H2O

If the chromate ion is produced at an instantaneous rate of 0.0065 mol/L/s at a particular temperature, what is the rate of reaction? ( Answer to 2 significant figures)

Answer 1

it is done withthe ratioos in the equation:

2CrO2- &  3 H2O2 &  2OH-   -->  2CrO42-  &  4H2O

rates of reaction:

in appearance  of (CrO4)-2 : rate of 0.0065 mol/L/s

in appearance  of H2O : rate of 0.013 mol/L/s

in disappearance  of (CrO2)- : rate of 0.0065 mol/L/s

in disappearance  of H2O2 : rate of 0.0098 mol/L/s

in disappearance  of (OH)- : rate of 0.0065 mol/L/s