CBSE Class 12 · 2005 · All India Compartment; also 2006 · Chemical KineticsShort Answer

The rate of a reaction increases sixteen times when the concentration of the reactant increases four times. The order of the reaction is

Assertion (A): The units of the rate constant of a zero order reaction and of the rate of reaction are the same.
Reason (R): In a zero order reaction, the rate of reaction is independent of the concentration of the reactants.

Show that in the case of a first order reaction, the time taken for completion of 99% of the reaction is twice the time required for 90% completion of the reaction. (log 10 = 1)

The rate constant of a reaction quadruples when the temperature changes from 300 K to 320 K. Calculate the activation energy for this reaction. (log 2 = 0.30, log 4 = 0.60, 2.303 R = 19.15 J K${}^{-1}$ mol${}^{-1}$)

What happens to the rate constant k and the activation energy E${}_a$ as the temperature of a chemical reaction is increased? Justify.

(a) For the reaction $2{\mathrm{N}}_2{\mathrm{O}}_5(\mathrm{g})\to 4\mathrm{N}{\mathrm{O}}_2(\mathrm{g})+{\mathrm{O}}_2(\mathrm{g})$ at 318 K, calculate the rate of reaction if the rate of disappearance of N${}_2$O${}_5$(g) is $1.4\times 10^{-3}$ M s${}^{-1}$.
(b) For a first order reaction, derive the relationship t${}_{99\%}$ = 2 t …