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NEET · Chemistry · STD 12 - 3. Chemical kinetics

A first order reaction has a specific reaction rate of \(10^{-2}\,sec^{-1}.\) How much time will it take for \(20\, g\) of the reactant to reduce to \(5\, g\,?\) ........ \(\sec\)

  1. A \(138.6\)
  2. B \(346.5\)
  3. C \(693.0\)
  4. D \(238.6\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(138.6\)

Step-by-step Solution

Detailed explanation

\(\mathrm{t}=\frac{2.303}{\mathrm{K}} \log \frac{[ \mathrm{A} ]_{\mathrm{o}}}{\left[\mathrm{A}]_{\mathrm{t}}\right.}\) \(\mathrm{t}=\frac{2.303}{10^{-2}} \log \frac{20}{5} \)\(\Rightarrow \mathrm{t}=138.6\, \mathrm{sec}\)