The rate of reaction can be increased by (more than one correct)

Options

A. Decreaisng threshold energy
B. Uisng a poistive catalyst
C. Increaisng activation energy
D. Increaisng temperature

Answer

To determine how the rate of a reaction can be increased, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Threshold Energy**:
- Threshold energy is the minimum energy required for reactant species to undergo an effective collision.
- If we decrease the threshold energy, more molecules will have sufficient energy to collide effectively, leading to an increase in the rate of reaction.
- **Conclusion**: Option A (decreasing threshold energy) is correct.

2. **Analyzing Temperature**:
- According to the Arrhenius equation, the rate constant (k) increases with an increase in temperature.
- As temperature increases, the kinetic energy of the molecules increases, leading to more frequent and effective collisions.
- **Conclusion**: Option D (increasing temperature) is correct.

3. **Examining Activation Energy**:
- Activation energy (Ea) is the energy barrier that must be overcome for a reaction to occur.
- If activation energy is increased, the rate constant (k) decreases according to the Arrhenius equation.
- Therefore, increasing activation energy will decrease the rate of reaction.
- **Conclusion**: Option C (increasing activation energy) is incorrect.

4. **Considering Catalysts**:
- A positive catalyst increases the rate of reaction by providing an alternative pathway with a lower activation energy.
- This means that the presence of a catalyst allows more collisions to be effective, thus increasing the rate of reaction.
- **Conclusion**: Option B (using a positive catalyst) is correct.

### Final Answer:
The options that can increase the rate of reaction are:
- A: Decreasing threshold energy
- B: Using a positive catalyst
- D: Increasing temperature