For a reaction whose rate law is: rate=k[X], a plot of which of the following is a straight line?

For a reaction whose rate law is: rate=k[X], a plot of which of the following is a straight line?

A. [X] versus time

B. ln[X] versus time

C. 1/[X] versus time

D. [X] versus 1/time

Solution: The rate law tells us the reaction is first order since [X] is to the power of 1. For first order reactions, straight line is seen when ln[X] versus time is plotted. B is the correct answer choice.