Solveeit Logo
Login

Question

Question: In a first order reaction the concentration of reactant decrease from \(400molL^{- 1}\) to \(25molL^...

In a first order reaction the concentration of reactant decrease from 400molL−1400molL^{- 1} to 25molL−125molL^{- 1} in 200 seconds. The rate constant for the reaction is

A

1.01386s−11.01386s^{- 1}

B

2×10−4s−12 \times 10^{- 4}s^{- 1}

C

1.386×10−2s−11.386 \times 10^{- 2}s^{- 1}

D

3.4×10−4s−13.4 \times 10^{- 4}s^{- 1}

Answer

1.386×10−2s−11.386 \times 10^{- 2}s^{- 1}

Explanation

Solution

For first order reaction,

k=2.303tlog⁡aa−x=2.303200log⁡40025k = \frac{2.303}{t}\log\frac{a}{a - x} = \frac{2.303}{200}\log\frac{400}{25}

=2.303200×1.204=0.01386s−1=1.386×10−2s−1= \frac{2.303}{200} \times 1.204 = 0.01386s^{- 1} = 1.386 \times 10^{- 2}s^{- 1}