For a ZERO-ORDER reaction $A \to \text{products}$, which graph is a STRAIGHT LINE?

1. For zero order, $\text{rate} = -d[A]/dt = k[A]^0 = k$. 2. Integrate: $-d[A] = k\,dt \Rightarrow [A] = [A]_0 - k\,t$. 3. This is the equation of a STRAIGHT LINE with $[A]$ on the y-axis, $t$ on the x-axis, slope $-k$, and y-intercept $[A]_0$. 4. Option B is the FIRST-order straight-line plot ($\ln[A]$ vs $t$). Option C is the SECOND-order straight-line plot ($1/[A]$ vs $t$). Option D doesn't yield a linear relationship for any standard order. 5. These linear plots are how chemists EXPERIMENTALLY determine the order of a reaction: try plotting each linearisation; the one that gives a straight line tells you the order. _Source: NCERT Class 12 Chemistry Part 1, Ch 3, §3.3.1 (Zero Order Reactions, integrated form), p. 12._