Question

For the zero order reaction $A\to B+C;$ initial concentration of $A$ is $0.1M.$ If $A=0.08M$ after $10$ minutes, then it's half-life and completion time are respectively :

• A. $10$ min $;20$ min
• B. $2\times {10}^{-3}$ min $;4\times {10}^{-3}$ min
• C. $25$ min $;50$ min
• D. $250$ min $;500$ min

Answer 1

Answer: (C)

$25$ min $;50$ min

Its a Zero Order Reaction.

$k=\frac{\left[A_0\right]-\left[A\right]}{t}$

$k=\frac{\left[0.1\right]-\left[0.08\right]}{10}$ = $2\times {10}^{-3}M{min}^{-1}$

$t_{1/2}=\frac{\left[A_0\right]}{2k}$

$t_{1/2}=25min$

$t=\frac{\left[A_0\right]}{k}$

$t=50min$