Question

Q. Hydrogen peroxide , H2O2(aq) decomposes to H2O (l) and O2 (g) in a reaction that is first order in H2O2
and has a rate constant k= 1.06 X 10-3 min -1.
(i) How long it will take 15 % of a sample of H2O2 to decompose ?
(ii) ​ How long it will take 85 % of a sample to decompose ?

Answer 1

Answer:i) 2.55 hours of time require to decompose 15% of hydrogen peroxide sample.

ii)29.83 hours of time require to decompose 85% of hydrogen peroxide sample.

Explanation:

The integrated expression of first order reaction:

$kt=2.303\log\frac{[A_o]}{[A]}$[/tex]

k = rate constant, [A] = concentration of sample at time t.

$[A_o]$ = initial concentration

i) time taken 15 % of a sample of $H_2O_2$ to decompose:

$[A]=A_o-15\%[A_o]=0.85[A_o]$

$1.06\times 10^{-3} min^{-1}t=2.303\log\frac{[A_o]}{[0.85A_o]}$

$t_{15\%}=153.34 min=2.55 hours(1 hour=60 min)$

ii) time taken 85 % of a sample of $H_2O_2$ to decompose:

$[A]=A_o-85\%[A_o]=0.15[A_o]$

$1.06\times 10^{-3} min^{-1}t=2.303\log\frac{[A_o]}{[0.15A_o]}$

$t_{15\%}=1790 min=29.83 hours$

Answer 2

Answer:

Explanation:

See this in image for solution