JEE Main 2025 Jan 23 Shift 2, Chemistry Q12: Reactions of Various Orders

For a zero-order reaction $A\to P$, the rate law is $-\frac{d[A]}{dt}=k$, so the rate is constant and independent of $[A]$.

Integrating gives $[A{]}_t=[A{]}_0-kt$, a straight line of negative slope when reactant concentration is plotted against time.

The graph showing reactant concentration decreasing linearly with time matches option (2).