Question

The rate law for a reaction $A+B⟶productisrate=K{\left[A\right]}^1{\left[B\right]}^2$. Then which one of the following statement is false?

• A. If [B] is held constant while [A] is doubled, the reaction will proceed twice as fast
• B. If [A] is held constant while [B] is reduced to one quater, the rate will be halved
• C. If [A] and [B] are both doubled, the reaction will proceed 8 times as fast
• D. This is a third order reaction

Answer 1

The correct option is B If [A] is held constant while [B] is reduced to one quater, the rate will be halved

Here the rate can be given as:

$rate=k\left[A\right][B{]}^2$

Thus, the rate is first order in A and second order in B and overall order of reaction is 3.

So, when [A] is double while the concentration of B is kept constant, the rate will be doubled.

Also, when the concentration of A is kept constant and concentration of B is reduced to one quarter than the rate of reaction will be decreased by $\frac{1}{16}$