Which of the following are soluble in excess of `NaOH`
(X) :`As_(2)S_(3)` ,(Y) : `CuS` ,(Z) : `AICI_(3)`

Options

A. X,Y,Z
B. Y,Z
C. X,Z
D. X,Y

Answer

To determine which of the given compounds are soluble in excess of NaOH, we will analyze each compound one by one.

### Step 1: Analyze Arsenic Sulfide (As₂S₃)
- Arsenic sulfide (As₂S₃) is known to react with excess NaOH to form sodium meta-arsenate (Na₃AsO₄) and sodium sulfide (Na₂S).
- Therefore, As₂S₃ is soluble in excess NaOH.

### Step 2: Analyze Copper Sulfide (CuS)
- Copper sulfide (CuS) is generally insoluble in excess NaOH. It does not react with NaOH to form any soluble products.
- Therefore, CuS is not soluble in excess NaOH.

### Step 3: Analyze Aluminum Chloride (AlCl₃)
- Aluminum chloride (AlCl₃) reacts with excess NaOH to form sodium aluminate (NaAlO₂).
- Therefore, AlCl₃ is soluble in excess NaOH.

### Conclusion:
- From the analysis, we find that:
- As₂S₃ is soluble in excess NaOH.
- CuS is not soluble in excess NaOH.
- AlCl₃ is soluble in excess NaOH.

Thus, the compounds that are soluble in excess NaOH are As₂S₃ and AlCl₃.

### Final Answer:
The compounds that are soluble in excess NaOH are:
- (X) As₂S₃
- (Z) AlCl₃