Question

For the reaction, $2N_2{O}_5⟶4N{O}_2+O_2$ the value of rate constant and rate of reaction are respectively $3\times {10}^{-5}{s}^{-1}$ and $2.4\times {10}^{-5}M{s}^{-1}$. The concentration of $N_2{O}_5$ (in mol L ${}^{-1}$) will be:

• A. $0.4$
• B. $0.8$
• C. $1.2$
• D. $0.6$

Answer 1

The correct option is B $0.8$

For the reaction, $2N_2{O}_5⟶4N{O}_2+O_2$ the value of rate constant and rate of reaction are respectively $3\times {10}^{-5}{s}^{-1}$ and $2.4\times {10}^{-5}M{s}^{-1}$. The concentration of $N_2{O}_5$ (in mol L${}^{-1}$) will be 0.8 M.
The unit of rate constant $s^{-1}$ indicates that the order of the reaction is $1^{st}$ order .
Now,

$\text{rate}=k\left[N_2{O}_5\right]$

$2.4\times {10}^{-5}M{s}^{-1}=3\times {10}^{-5}{s}^{-1}\times \left[N_2{O}_5\right]$

$\left[N_2{O}_5\right]=0.8$ M.