Question

For the following reaction, $N{O}_2\left(g\right)+CO\left(g\right)\to NO\left(g\right)+C{O}_2\left(g\right)$, the rate law is
Rate $=k[N{O}_2{]}^2$. If 0.1 mole of gaseous carbon monoxide is added at constant temperature to the reaction mixture which of the following statements is true?

• A. Both $k$ and the reaction rate remain the same
• B. Both $k$ and the reaction rate increase
• C. Both $k$ and the reaction rate decrease
• D. Only $k$ increases, the reaction rate remain the same
• E. Only the reaction rate increases, $k$ remains the same

Answer 1

Answer: (A)

Both $k$ and the reaction rate remain the same

$N{O}_2\left(g\right)+CO\left(g\right)\to NO\left(g\right)+C{O}_2\left(g\right)$

$\because$ Rate of reaction, $\left(\frac{dx}{dt}\right)=k[N{O}_2{]}^2$

$\therefore$ Rate is independent of $CO$.

Hence, on adding more $CO$ to the reaction mixture, both $k$ and rate remain the same.