Question

For the zero order reaction $A\to 2B$, the rate constant is $2\times {10}^{-6}M$ ${min}^{-1}$. The reaction is started with $10M$ $A$.
(i) What will be the concentration of A after 2 days (ii) What is the initial half-life of the reaction
(iii) In what time, the reaction will complete?

Answer 1

Here $K_t=a_o-a_t$

$a_o=10M,K=2\times {10}^{-6}Mmi{n}^{-1}$

(i) $t=2$ days= $42\times 24\times 60=2880$ mins

$\therefore 2\times {10}^{-6}\times 2880=10-a_t$

$\therefore a_t=10-0.00576=9.99424M$

(ii) At half life time, $a_t=\frac{a_o}{2}$

$\therefore t_{1/2}=\frac{a_o}{2K}=\frac{10}{2\times 1\times {10}^{-6}}=2.5\times {10}^{6}min$

(iii) At completion, $a_t=0$

$\therefore t=\frac{a_o}{K}=\frac{10}{2\times {10}^{-6}}=5\times {10}^6$ min