# NEET Chemistry Chemical Kinetics Questions Solved

BOARD

The thermal decomposition of is a first order reaction with a rate constant of 2.4 $×$10-3 s-1 at a  certain temperature. Calculate how long will it take for three-fourths of initial quantity ofto decompose. (log 0.25 = -0.6021)

Given: K=2.4 $×$10-3

According to the formulas, where $\left[\begin{array}{c}\begin{array}{c}a=1\\ K=2.4×{10}^{-3}\\ x=\frac{3}{4}=0.75\end{array}\begin{array}{}\\ \\ \end{array}\\ \end{array}\right]$

t = $\frac{2.303}{K}$ log$\frac{1}{1-0.75}$

or      t = $\frac{2.303}{2.4×{10}^{-3}}$ log 0.25

or      t = $\frac{2.303}{2.4×{10}^{-3}}$ $×$ 0.6020

or      t = $\frac{1.386406}{2.4×{10}^{-3}}$  = 577.6

$\therefore$ Time taken,  t = 577.6 sec.

Difficulty Level:

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