Question

Reactant ‘A’ underwent a decomposition reaction. The concentration of ‘A’ was measured periodically and recorded in the table given below:

Time (Hours)	[A] (M)
0	0.40
1	0.20
2	0.10
3	0.05

Based on the above data, predict the order of the reaction and write the expression for the rate law.

Hint:

For first-order reactions, the natural logarithm of concentration vs time should yield a straight line.

Answer 1

We can ascertain the reaction order using integrated rate law equations for various reaction orders. The reaction order can be identified by plotting concentration versus time data. A linear plot of ln[A] against time signifies a first-order reaction. The provided data confirms the reaction is first-order. Consequently, the rate law is: \[\text{Rate} = k[A]\]