Question

At $300K$ rate constant for $A\to$ product at $t=50$ min is $0.02s^{-1}$, then rate constant at $t=75$ min and $310K$ will be (in $s^{-1}$)

• A. $\frac{0.4}{25}$
• B. $0.04\times 25$
• C. $0.04$
• D. $\frac{0.02}{25}$

Answer 1

The correct option is A $\frac{0.4}{25}$

$Givenk=0.02s^{-1}$

$t_1=50s{t}_2=75s$

$log\frac{{\left[R\right]}_0}{\left[R\right]}=\frac{kt}{2.303}=\frac{0.02\times 50}{2.303}=0.43$

For second condition

$k=\frac{1}{t2-t1}log\frac{{\left[R\right]}_1}{[{R]}_2}$

$=\frac{1}{75-50}\times 0.4$

$=\frac{0.4}{25}$

Hence, the correct option is $A$