An emulsion cannot be broken by `cdots ` and
a) heating
b) adding more amount of dispersion medium
c) freezing
d) adding emulsifying agent

Options

A. b,d
B. a,b
C. b,c
D. c,d

Explanation

To solve the question regarding which methods cannot break an emulsion, we need to understand the nature of emulsions and the effects of different actions on them.

### Step-by-Step Solution:

1. **Understanding Emulsions**:
- An emulsion is a type of colloid where two immiscible liquids are mixed together, with one liquid (the dispersed phase) being dispersed in the other (the dispersion medium). Common examples include oil in water or water in oil.

2. **Identifying the Options**:
- The options given are:
a) heating
b) adding more amount of dispersion medium
c) freezing
d) adding emulsifying agent

3. **Analyzing Each Option**:
- **Option a: Heating**: Heating can cause the emulsion to break down as it can increase the kinetic energy of the molecules, leading to the separation of the two phases.
- **Option b: Adding more amount of dispersion medium**: This action dilutes the emulsion, which can stabilize it rather than break it. Thus, this option does not break the emulsion.
- **Option c: Freezing**: Freezing can also lead to the separation of the two phases, breaking the emulsion.
- **Option d: Adding emulsifying agent**: An emulsifying agent stabilizes the emulsion, preventing the two liquids from separating. Therefore, it does not break the emulsion.

4. **Conclusion**:
- The two actions that cannot break an emulsion are:
- **b) adding more amount of dispersion medium**
- **d) adding emulsifying agent**

Thus, the correct answer is **b and d**.