How many of the following salts give precipitate with aq. NaOH solution which dissolve in excess of the reagent?
`CdSO_(4), Pb(NO_(3))_(2), CrCI_(3). MnCI_(2). ZnSO_(4). CuSO_(4). Bi(NO_(3))_(3), SnCI_(4)`

Explanation

To determine how many of the given salts give a precipitate with aqueous NaOH solution that dissolves in excess reagent, we will analyze each salt one by one.

### Step-by-Step Solution:

1. **Identify the Salts:**
The salts given are:
- CdSO₄
- Pb(NO₃)₂
- CrCl₃
- MnCl₂
- ZnSO₄
- CuSO₄
- Bi(NO₃)₃
- SnCl₄

2. **Reactions with Aqueous NaOH:**
We will check each salt to see if it forms a precipitate with NaOH and if that precipitate dissolves in excess NaOH.

- **CdSO₄:**
- Reaction: CdSO₄ + 2 NaOH → Cd(OH)₂ (s) + Na₂SO₄
- Cd(OH)₂ is a precipitate but does not dissolve in excess NaOH.
- **Conclusion:** Does not meet the criteria.

- **Pb(NO₃)₂:**
- Reaction: Pb(NO₃)₂ + 2 NaOH → Pb(OH)₂ (s) + 2 NaNO₃
- Pb(OH)₂ is a white precipitate that dissolves in excess NaOH to form Na₂PbO₂.
- **Conclusion:** Meets the criteria.

- **CrCl₃:**
- Reaction: CrCl₃ + 3 NaOH → Cr(OH)₃ (s) + 3 NaCl
- Cr(OH)₃ is a green precipitate that dissolves in excess NaOH to form Na₂CrO₄.
- **Conclusion:** Meets the criteria.

- **MnCl₂:**
- Reaction: MnCl₂ + 2 NaOH → Mn(OH)₂ (s) + 2 NaCl
- Mn(OH)₂ is a precipitate but does not dissolve in excess NaOH.
- **Conclusion:** Does not meet the criteria.

- **ZnSO₄:**
- Reaction: ZnSO₄ + 2 NaOH → Zn(OH)₂ (s) + Na₂SO₄
- Zn(OH)₂ is a white precipitate that dissolves in excess NaOH to form Na₂ZnO₂.
- **Conclusion:** Meets the criteria.

- **CuSO₄:**
- Reaction: CuSO₄ + 2 NaOH → Cu(OH)₂ (s) + Na₂SO₄
- Cu(OH)₂ is a blue precipitate that does not dissolve in excess NaOH.
- **Conclusion:** Does not meet the criteria.

- **Bi(NO₃)₃:**
- Reaction: Bi(NO₃)₃ + 3 NaOH → Bi(OH)₃ (s) + 3 NaNO₃
- Bi(OH)₃ is a white precipitate that does not dissolve in excess NaOH.
- **Conclusion:** Does not meet the criteria.

- **SnCl₄:**
- Reaction: SnCl₄ + 4 NaOH → Sn(OH)₄ (s) + 4 NaCl
- Sn(OH)₄ is a white precipitate that dissolves in excess NaOH to form Na₂SnO₃.
- **Conclusion:** Meets the criteria.

3. **Count the Salts that Meet the Criteria:**
The salts that give a precipitate with NaOH and that precipitate dissolves in excess NaOH are:
- Pb(NO₃)₂
- CrCl₃
- ZnSO₄
- SnCl₄

Thus, there are **4 salts** that meet the criteria.

### Final Answer:
**4 salts give a precipitate with aqueous NaOH solution which dissolves in excess of the reagent.**