  Question

For a reactions $$A+B\rightarrow product$$, it was found that rate of reaction increases four times if concentration of 'A' is doubled, but the rate of reaction remains unaffected, if concentration of 'B' is doubled. Hence, the rate law for the reaction is: $$[MP PET/PMT 1998; MP PMT 2003]$$

A
rate=k[A][B]  B
rate=k[A]2  C
rate=k[A]2[B]1  D
rate=k[A]2[B]2  Solution

The correct option is C $$rate=k\left[A\right]^{2}$$Let the rate of reaction depends on $$x$$ power of $$\left[A\right]$$. Then$$r_{1}=k\left[A\right]^{x}$$ and $$r_{2}=k\left[2A\right]^{x}$$$$\therefore\dfrac{r_1}{r_2}=\dfrac{\left[A\right]^{x}}{\left[2A\right]^{x}}=\dfrac{1}{4}=\left(\dfrac{1}{2}\right)^{2} \, \, \,\left(\because{r_{2}=4r_1}\right)$$$$\therefore{x=2}$$, As the reaction rate does not depend upon the concentration of $$B$$. Hence, the correct rate law will be $$rate=K\left[A\right]^{2}\left[B\right]^{o}$$ or $$=K\left[A\right]^{2}$$ChemistryNCERTStandard XII

Suggest Corrections  0  Similar questions
View More  Same exercise questions
View More  People also searched for
View More 