The rate of the reaction at `40^(@)C` is 5 units, then the rate of same reaction at `80^(@)C` is (nearly)

Options

A. 10 units
B. 40 units
C. 20 units
D. 80 units

Answer

To determine the rate of the reaction at `80°C`, given that the rate at `40°C` is `5 units`, we can use the empirical observation that the rate of a reaction approximately doubles with every increase of `10°C` in temperature.

### Step-by-Step Solution:

1. **Identify the Initial Rate and Temperature**:
- The rate of the reaction at `40°C` is given as `5 units`.

2. **Determine the Temperature Increase**:
- We need to find the rate at `80°C`. The temperature increase from `40°C` to `80°C` is `40°C`.

3. **Calculate the Number of 10°C Increments**:
- From `40°C` to `80°C`, there are `4` increments of `10°C` (i.e., `40°C` to `50°C`, `50°C` to `60°C`, `60°C` to `70°C`, and `70°C` to `80°C`).

4. **Apply the Doubling Rule**:
- Since the rate doubles with each `10°C` increase:
- At `50°C`: Rate = `5 units * 2 = 10 units`
- At `60°C`: Rate = `10 units * 2 = 20 units`
- At `70°C`: Rate = `20 units * 2 = 40 units`
- At `80°C`: Rate = `40 units * 2 = 80 units`

5. **Conclusion**:
- Therefore, the rate of the reaction at `80°C` is `80 units`.

### Final Answer:
The rate of the reaction at `80°C` is **80 units**.