A mixture contains four solid compounds A, B, C, D. On heating C changes to vapour state. C can be separated from rest of the solids by

Options

A. crystallisation
B. sublimation
C. distillation
D. filtration

Explanation

To solve the question regarding the separation of solid compound C from a mixture containing four solid compounds A, B, C, and D, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Properties of Compound C**:
- The question states that compound C changes to vapor state upon heating. This indicates that C undergoes sublimation, which is the process where a solid turns directly into a gas without passing through the liquid phase.

2. **Identifying the Separation Technique**:
- Since C sublimates, we can separate it from the other solid compounds (A, B, and D) by heating the mixture. As the mixture is heated, C will vaporize, leaving behind the other solid compounds.

3. **Collecting the Vapor**:
- The vapor of compound C can then be collected and cooled down to obtain C back in solid form if needed. This process is effective because the other solids (A, B, D) do not change state upon heating.

4. **Conclusion**:
- The best method to separate compound C from the mixture is through sublimation. Therefore, the answer to the question is that C can be separated from the rest of the solids by sublimation.

### Final Answer:
C can be separated from the rest of the solids by **sublimation**.

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