Solveeit Logo
Login

Question

Chemistry Question on Chemical Kinetics

In first order reaction, the concentration of reactant decreases from 800 mol cm−3800\, mol\, cm ^{-3} to 50 mol cm−350\, mol\, cm ^{-3} in 2×104s2 \times 10^{4} s. The rate constant is

A

2×104s−1 2\times 10^{4}s^{-1}

B

3.45×10−5s−13.45 \times 10^{-5} s^{-1}

C

1.386×10−4s−11.386 \times 10^{-4} s ^{-1}

D

2×10−4s−12 \times 10^{-4} s^{-1}

Answer

1.386×10−4s−11.386 \times 10^{-4} s ^{-1}

Explanation

Solution

For first order reaction, Rate constant,
k=2.303tlog⁡aa−xk=\frac{2.303}{t} \log \frac{a}{a-x}
⇒k=2.3032×104log⁡80050\Rightarrow k=\frac{2.303}{2 \times 10^{4}} \log \frac{800}{50}
=1.386×10−4s−1=1.386 \times 10^{-4} s^{-1}