Question

For the reaction, $2A + B \to $ products, when the concentrations of A and B both where doubled , the rate of the reaction increased from $0.3 \; mol \; L^{-1} s^{-1 }$ to $2.4 \; mol \; L^{-1} s^{-1}$. When the concentration of A alone is doubled, the rate increased from $0.3 \; mol \; L^{-1} s^{-1}$ to $0.6 \; mol \; L^{-1} s^{-1}$
Which one of the following statements is correct ?

• A. Order of the reaction with respect to $B$ is $2$
• B. Order of the reaction with respect to $A$ is $2$
• C. Total order of the reaction is $4$
• D. Order of the reaction with respect to $B$ is $1$

Answer 1

Answer: (A)

$r = K[A]^x [B] ^y$
$\Rightarrow \; 8 = 2^3 = 2^{x+y}$
$\Rightarrow \; x + y = 3$ ...(1)
$\Rightarrow \; 2 = 2^x$
$ \Rightarrow \; x = 1, y = 2$
Order w.r.t. $A = 1$
Order w.r.t. $B = 2$