The decomposition of hydrogen peroxide in the presence of iodide ion has been found to be first order in `H_2O_2`:
`2H_2O_2 (aq) overset(1^(-)(aq))(rarr) 2H_2O(l) + O_2 (g)`.
The rate constant has been found to be `1.01 xx10^(-2) " min"^(-1)` :
(a) Calculate the rate of reaction when `[H_2O_2] = 0.4" mol lit"^(-1)`.
(b) What concentration of `[H_2O_2]` would give a rate of `1.12 xx 10^(-2)" mol lit"^(-1)" min"^(-1)` ?

Explanation

(i) Rate = `k [H_2O_2]`
`= 0.4 xx 1.01 xx 10^(-2)`
`= 4.04 xx 10^(-3) mol l^(-1) "min"^(-1)`
(ii) Rate =`k [H_2O_2]`
`= 0.15 xx 1001 xx 10^(-2)`
`= 1.51 xx 10^(-3) mol l^(-1)" min"^(-1)`
(iii) Rate = `k [H_2O_2]`
` 1.12 xx 10^(-2) = 1.01 xx 10^(-2) xx [H_2O_2]`
`[H_2O_2] = 1.11 mol l^(-1) "min"^(-1)`