A reaction is of first order in reactant A and of second order in reactant B. How is rate of reaction affected when
(a) Concentration of B alone is increased to three times.
(b) The concentration of A as well as B is doubled.

Explanation

We know that,
Rate of reaction = `k [B]^3[A]`
When B is increased to three times,
`A+3B to` Product
Rate of reaction = `k [B]^2 [A] `
` = 9k. [B] [A] `
`= 9 (k [B]^2 [A])`
Rate of reaction = `k [B]^2 [A]`
When B is doubled as well as A
`2 A+2B to` Product
Rate of reaction = `k [2A][2B]^2`
`= 8 (k[A][B]^2)`