Which of the following graphs is correct for a zero order reaction ?

Options

A.
B.
C.
D.

Explanation

### Step-by-Step Solution:

1. **Understanding Zero Order Reactions**:
- A zero-order reaction is characterized by a constant rate that does not depend on the concentration of the reactants. The rate of reaction can be expressed as:
\[ \text{Rate} = k \]
- Here, \( k \) is the rate constant, and it remains constant regardless of the concentration of the reactant.

2. **Rate vs. Time Graph**:
- For a zero-order reaction, the rate remains constant over time until the reactant is depleted. Therefore, the graph of the rate versus time would be a horizontal line, indicating that the rate does not change as time progresses.

3. **Concentration vs. Time Graph**:
- The concentration of the reactant decreases linearly over time for a zero-order reaction. The relationship can be expressed as:
\[ [A]_t = [A]_0 - kt \]
- This indicates that the concentration decreases at a constant rate. The graph of concentration versus time will be a straight line with a negative slope.

4. **Identifying the Correct Graph**:
- Based on the characteristics of a zero-order reaction:
- The correct graph for concentration vs. time will show a straight line with a negative slope.
- The rate vs. time graph will be a horizontal line.

5. **Conclusion**:
- The correct graphs for a zero-order reaction are:
- A horizontal line for the rate vs. time graph.
- A straight line with a negative slope for the concentration vs. time graph.