Question
The rate constant, the activation energy and the Arrhenius parameter of a chemical reaction at $${25^ \circ }C$$ are $$3.0 \times {10^{ - 4}}{s^{ - 1}},$$ $$104.4\,kJ\,mo{l^{ - 1}}$$ and $$6.0 \times {10^{14}}{s^{ - 1}}$$ respectively. The value of the rate constant as $$T \to \infty $$ is,
A.
$$2.0 \times {10^{18}}{s^{ - 1}}$$
B.
$$6.0 \times {10^{14}}{s^{ - 1}}$$
C.
$${\text{infinity}}$$
D.
$$3.6 \times {10^{30}}{s^{ - 1}}$$
Answer :
$$6.0 \times {10^{14}}{s^{ - 1}}$$
Solution :
The Arrhenius equation is $${\text{:}}\,\,k = A\,\exp \left( { - {E_a}/RT} \right)$$
as $$T \to \infty ,\,\exp \left( { - {E_a}/RT} \right) \to 1.$$ Hence, $$k=A$$
where $$A,$$ the Arrhenius parameter is $$6.0 \times {10^{14}}{s^{ - 1}}$$
[ NOTE : $$'A'$$ is also known as frequency factor ]