Question

For a reaction, $A⟶B+C.$ it was found that at the end of 10 minutes from the start, the total optical rotation of the system was ${50}^0$ and when the reaction is complete, it was ${100}^0$. Assuming that only B and C are optically active and dextro rotatory the rate constant of this first order reaction would be

Answer 1

As when reaction is complete. The total optical rotation is ${100}^{\circ }$.

As the reaction is first order at half concentration the time is called life time.

Here half time is given as 10 minutes.

As $t1/2=\frac{0.693}{k}$

$\Rightarrow 10minutes=\frac{0.693}{k}$

$k=0.0693mi{n}^{-1}$

So, Rate constant is $0.0693mi{n}^{-1}$