Sucrose decomposes in acid solution into glucose and fructose according to the first order rate law,with $t_{1/2} = 3.00 \ h$. What fraction of sample of sucrose remains after $8 \ h$ $?$

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) For a first order reaction,the rate constant $k$ is given by $k = \frac{0.693}{t_{1/2}}$.
Given $t_{1/2} = 3.00 \ h$,we have $k = \frac{0.693}{3.00 \ h} = 0.231 \ h^{-1}$.
The integrated rate law for a first order reaction is $\ln \frac{[R]_0}{[R]} = kt$ or $\log \frac{[R]_0}{[R]} = \frac{kt}{2.303}$.
Substituting the values: $\log \frac{[R]_0}{[R]} = \frac{0.231 \ h^{-1} \times 8 \ h}{2.303} = \frac{1.848}{2.303} \approx 0.8024$.
Taking the antilog,$\frac{[R]_0}{[R]} = 10^{0.8024} \approx 6.3445$.
The fraction remaining is $\frac{[R]}{[R]_0} = \frac{1}{6.3445} \approx 0.1576$.
Thus,the fraction of sucrose remaining after $8 \ h$ is approximately $0.158$.

Explore More

Similar Questions

Consider the first order reaction $R \to P$. The fraction of molecules decomposed in the given first order reaction can be expressed as:

Among the following statements,the correct statement about the half-life period for a first order reaction is

$A$ first order reaction is $60\%$ complete in $20 \text{ minutes}$. How long will the reaction take to complete $84\%$ (in $\text{ min}$)?

$t_{87.5}$ is the time required for the reaction to undergo $87.5 \%$ completion and $t_{50}$ is the time required for the reaction to undergo $50 \%$ completion. The relation between $t_{87.5}$ and $t_{50}$ for a first order reaction is $t_{87.5} = x \times t_{50}$. The value of $x$ is $......$. (Nearest integer)

Which equation is correct for first order reactions?

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo