(a) For a reaction A+BrarrP, the rate is given by Rate =K[A][B]^(2) (i) How is the rate of reaction affected if the concentration of B is doubled ? (ii) What is the overall order of reaction if A is present in large excess ? (b) A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.

(a) For a reaction A+BrarrP, the rate is given by Rate =K[A][B]^(2) (

1.	(a) For a reaction A+BrarrP, the rate is given by Rate =K[A][B]^(2) (i) How is the rate of reaction affected if the concentration of B is doubled ? (ii) What is the overall order of reaction if A is present in large excess ? (b) A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.
Answer» SOLUTION :(a) (i) `A+BrarrP" Rate "=k[A] [B]^(2)` Differential rate equation of REACTION is `(dn)/(dt)=k[A]'[B]^(2)=k[A][B]^(2)` When concentration of B is doubled it means concentration of B becomes `[2xxB]" "therefore` New rate of reaction, `(dn)/(dt)=k[A] [2B]^(2)=4k[A] [B]^(2)=4[(dn)/(dt)]` i.e., rate of reaction will become 4 times. (ii) A useful protocol for determining the order of reaction with respect to a particular components is to measure the concentration dependence of rate when all other REACTANTS are in great EXCESS. `v=K[A]_("excess")^(a)[B]^(2)` `v=K'[B]^(2)["Over all order "=2]` `k'=K[A]_("excess")^(a)`