Question

The rate of decomposition of a substance A becomes eight times when its concentration is doubled. What is the order of this reaction?

Answer 1

Given:

When [A] is doubled, the rate becomes 8 times.

We are to find the order of reaction n.

Rate ∝ [A]ⁿ

Let’s take the ratio of the new rate to the original rate:

\[\ce{\frac{New rate}{Original rate} = (\frac{[A]_{new}}{[A]_{original}})^n}\]

\[\ce{\frac{8}{1} = (\frac{2}{1})^n}\]

⇒ 8 = 2ⁿ

⇒ n = 3

Order of reaction = 3