Which of the following substances are soluble in NaOH solution?

Options

A. `Sn(OH)_(2)`
B. `Al(OH)_(3)`
C. `Bi(OH)_(3)`
D. `Pb(OH)_(2)`

Answer

To determine which of the given substances are soluble in NaOH solution, we will analyze each option based on their chemical behavior with NaOH.

### Step-by-Step Solution:

1. **Identify the substances:**
The substances given are:
- A) Sn(OH)₃ (Tin(III) hydroxide)
- B) Al(OH)₃ (Aluminum hydroxide)
- C) Bi(OH)₃ (Bismuth(III) hydroxide)
- D) Pb(OH)₂ (Lead(II) hydroxide)

2. **Understanding amphoteric nature:**
Amphoteric substances can react with both acids and bases. The substances we are analyzing (Sn, Al, Bi, Pb) are known to exhibit amphoteric behavior.

3. **Analyze each substance:**
- **A) Sn(OH)₃:**
- Reaction: Sn(OH)₃ + NaOH → Na₂[Sn(OH)₄]
- Conclusion: This forms a soluble complex, hence Sn(OH)₃ is soluble in NaOH.

- **B) Al(OH)₃:**
- Reaction: Al(OH)₃ + NaOH → Na₂[Al(OH)₄]
- Conclusion: This also forms a soluble complex, indicating that Al(OH)₃ is soluble in NaOH.

- **C) Bi(OH)₃:**
- Reaction: Bi(OH)₃ + NaOH → Bi(OH)₃ (remains unchanged)
- Conclusion: This forms a white precipitate and does not dissolve, so Bi(OH)₃ is not soluble in NaOH.

- **D) Pb(OH)₂:**
- Reaction: Pb(OH)₂ + NaOH → Na₂[Pb(OH)₄]
- Conclusion: This forms a soluble complex, indicating that Pb(OH)₂ is soluble in NaOH.

4. **Final Conclusion:**
Based on the analysis:
- **Soluble in NaOH:** Sn(OH)₃, Al(OH)₃, Pb(OH)₂
- **Not soluble in NaOH:** Bi(OH)₃

Thus, the substances that are soluble in NaOH solution are **A) Sn(OH)₃, B) Al(OH)₃, and D) Pb(OH)₂**.