Question

In the following reaction
$A\to B+C,$ rate constant is $0.001\text{M/s}$. If we start with $1$ $M$ of A, the concentration of $A$ and $B$ after 10 min are respectively:

• A. $0.5\text{M},0.5\text{M}$
• B. $0.6\text{M},0.4\text{M}$
• C. $0.4\text{M},0.6\text{M}$
• D. None of these

Answer 1

The correct option is C $0.4\text{M},0.6\text{M}$

$k=0.001\text{M/s}$ ($\therefore$ order = zero)

$\begin{array}{cccccc}& \text{A}& \to & \text{B}& +& \text{C}\\ t=0& 1M& & 0& & 0\\ \text{t = t}& (1-x)& & x& & x\end{array}$
$k=\frac{C_0-C_t}{t}\Rightarrow 0.001=\frac{1-C_t}{600}\Rightarrow C_t=1-0.6=0.4$
$\left[A\right]=C_t=0.4;\left[B\right]=C_0-C_t=0.6$