Which order of reaction produces a linear plot when concentration is graphed versus time?

• A. Third-order
• B. Zero-order
• C. Second-order
• D. First-order

Answer: (B)

Verified step by step guidance

1. Understand that the order of a reaction determines the mathematical relationship between concentration and time.
2. Recall that for a zero-order reaction, the rate law is given by \(\text{rate} = k\), which means the rate is constant and independent of concentration.
3. For a zero-order reaction, the integrated rate law is \([A] = -k t + [A]_0\), where \([A]\) is the concentration at time \(t\), \(k\) is the rate constant, and \([A]_0\) is the initial concentration.
4. Notice that this integrated rate law is a linear equation in the form \(y = mx + b\), where concentration \([A]\) plotted against time \(t\) yields a straight line with slope \(-k\).
5. Compare this to first-order and second-order reactions, where plotting concentration versus time does not produce a straight line; instead, other plots such as \(\ln[A]\) versus time or \$1/[A]$ versus time are linear.