The actlvation energy for the gas phase decomposition of isobutyl bromide is $211kJ.$

$(C{H}_3{)}_{2}CHC{H}_2$Brlongrightarrow$(C{H}_3{)}_{2}C=C{H}_2+HBr$

The rate constant at $657K$ is $0\mathrm{.}000196/$s$.$ The rate constant will be $0\mathrm{.}00112/$s at

K$.$

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