Question

For a zero order reaction, the plot of concentration of reactant vs time is
(Hint: Consider the intercept on the concentration axis)

• A. linear with +ve slope and non zero +ve intercept
• B. linear with -ve slope and non zero +ve intercept
• C. linear with - ve slope and zero intercept
• D. linear with + ve slope and zero intercept

Answer 1

Answer: (B)

Any reaction of zero order must obey the following equation
$[A]=-kt+[A{]}_0$ or $[A]=[A{]}_0+kt$
This shows that, the concentration of reactant decreases linearly with time, as it is an equation of a straight line $(y=mx+c)$, the plot of $[A]$ versus $t$ will be straight line with slope $=-k$ and intercept on the concentration axis $=[A{]}_0$ as shown in figure.

Plot of $[A]$ versus $t$ for a reaction of zero order.