The rate constant for a first order reaction at 300°C for which Ea is 35 kcal mol-1 and frequency constant is 1.45×1011s-1 is

Question

The rate constant for a first order reaction at 300°C for which Ea is 35 kcal mol-1 and frequency constant is 1.45×1011s-1 is (A) 10×10-2s-1 (B)  5.37×10-10s-1 (C)  5×10-4s-1 (D)  7.94×10-3s-1

Tardigrade Admin · Accepted Answer

log k=log A-(Ea/2.303 RT) log k=log(1.45×1011) -(35×103/2.303×2×573) log k=11.16-13.26=-2.1 Taking antilog, k=7.94×10-3 s-1

Q. The rate constant for a first order reaction at $30 0^{^{\circ}} C$ for which $E_{a}$ is $35 k c a l m o l^{- 1}$ and frequency constant is $1.45 \times 1 0^{11} s^{- 1}$ is

$10 \times 1 0^{- 2} s^{- 1}$

$5.37 \times 1 0^{- 10} s^{- 1}$

$5 \times 1 0^{- 4} s^{- 1}$

$7.94 \times 1 0^{- 3} s^{- 1}$

$l o g k = l o g A - \frac{E _{a}}{2.303 RT}$
$l o g k = l o g (1.45 \times 1 0^{11})$ $- \frac{35 \times 1 0 ^{3}}{2.303 \times 2 \times 573}$
$l o g k = 11.16 - 13.26 = - 2.1$
Taking antilog, $k = 7.94 \times 1 0^{- 3}$ $s^{- 1}$

Q. The rate constant for a first order reaction at 300∘C for which Ea​ is 35kcalmol−1 and frequency constant is 1.45×1011s−1 is

10×10−2s−1

5.37×10−10s−1

5×10−4s−1

7.94×10−3s−1