Question

The plot that represents the zero-order reaction is:

• A.

• B.

• C.

• D.

Hint:

For zero-order reactions, always focus on the linear relationship between concentration and time. The slope of the graph gives the negative value of the rate constant (\( -k \)).

Answer 1

The Correct Option is B

Analysis begins with the characteristics of a zero-order reaction. The defining aspect of zero-order kinetics is the independence of the reaction rate from reactant concentration. The rate law is expressed as: \[ r = k[\text{R}]^0 = k. \] This signifies a constant reaction rate throughout the process.

Graphical Representation: The integrated rate equation for a zero-order reaction is: \[ [\text{R}] = [\text{R}_0] - k t, \] where \( [\text{R}_0] \) denotes the initial concentration, \( k \) is the rate constant, and \( t \) represents time. Plotting \( [\text{R}] \) against \( t \) yields a linear graph with: - Slope = \( -k \) (negative due to diminishing concentration over time). - Y-intercept = \( [\text{R}_0] \). 

Verification of the Plot: The graphical representation can be confirmed through the following steps: 1. At \( t = 0 \): \( [\text{R}] = [\text{R}_0] \), aligning with the y-intercept. 2. At \( t = \frac{[\text{R}_0]}{k} \): \( [\text{R}] = 0 \), marking the time of complete reactant consumption. Consequently, the plot of \( [\text{R}] \) versus \( t \) is a straight line with a negative slope, consistent with the equation.

 Final Answer: (2)