When `CH_(3)OH(l)` is mixed in water:

Options

A. degree of Randomness (entropy) decreases due to formation of Hydrogen bond.
B. Entropy of surrounding decreases
C. Mixing is spontaneous and reversible process
D. All of the above are correct

Answer

To solve the question regarding the mixing of methanol (CH₃OH) with water, we will analyze the situation step by step.

### Step-by-Step Solution:

1. **Understanding the Components**:
- We have two substances: Methanol (CH₃OH) and Water (H₂O). Both are polar solvents and can mix with each other.

**Hint**: Identify the nature of the substances involved. Both are polar solvents.

2. **No Chemical Reaction**:
- When methanol is mixed with water, there is no chemical reaction occurring between the two. Instead, they simply form a solution.

**Hint**: Consider the interaction between the molecules of methanol and water. Are they reacting chemically or just mixing?

3. **Formation of a Solution**:
- The mixture of methanol and water results in a solution. This is because both liquids retain their chemical properties when mixed.

**Hint**: Think about what defines a solution. Does it involve a change in chemical identity?

4. **Entropy Considerations**:
- When two liquids are mixed, one might expect an increase in entropy (disorder). However, in this case, the mixing of methanol and water leads to a decrease in entropy.

**Hint**: Reflect on the concept of entropy. What happens to the arrangement of molecules when two liquids mix?

5. **Molecular Interaction**:
- At the molecular level, methanol molecules interact with water molecules, leading to the formation of an open ring structure. This specific arrangement reduces the overall disorder, hence decreasing entropy.

**Hint**: Visualize the molecular arrangement. How do the molecules interact, and what structure do they form?

6. **Conclusion**:
- Based on the analysis, the correct conclusion is that when methanol is mixed with water, the entropy of the system decreases due to the specific interactions between the molecules.

**Hint**: Summarize the findings. What is the final outcome regarding entropy when methanol and water are mixed?

### Final Answer:
When CH₃OH (methanol) is mixed with water, there is no chemical reaction, but a solution is formed. The entropy of the system decreases due to the molecular interactions that create an open ring structure.