Consider a reaction `2A +B to` Products. When the concentration of B alone was doubled, the half life did not change. When concentration of A alone was doubled, the rate increased by two times. The unit of rate constant for the reaction is:

Options

A. `s^(-1)`
B. `Lmol^(-1)s^(-1)`
C. no unit
D. `mol L^(-1)s^(-1)`

Answer

B

Explanation

b) According to available data, when the concentration of B alone was doubled while keeping that of A constant, `t_(1//2)` did not change. This happens for the first order reaction `t_(1//2) = 0.693/k`
Therefore, order of reaction with respect to B is one. similarly, when concentration of A alone was doubled while keeping that of B constant, the rate increased by two times. This means that order with respect to A is also one.
`therefore` order of reaction =`1+1=2`
Units of second order reaction =`Lmol^(-1)s^(-1)`