Which one of the following salt is most acidic in water?

Options

A. `NiCl_(2)`
B. `BeCl_(2)`
C. `FeCl_(3)`
D. `AlCl_(3)`

Explanation

To determine which salt is the most acidic in water, we need to analyze the salts based on the strength of their constituent acid and base. Here’s a step-by-step solution:

### Step 1: Identify the Salts
Let's consider the following salts:
1. Nickel(II) chloride (NiCl₂)
2. Beryllium hydroxide (Be(OH)₂)
3. Iron(III) chloride (FeCl₃)
4. Aluminum chloride (AlCl₃)

### Step 2: Analyze the Constituent Acid and Base
For each salt, we need to identify the acid and base from which it is derived:
- **NiCl₂**: Derived from nickel hydroxide (Ni(OH)₂, a weak base) and hydrochloric acid (HCl, a strong acid).
- **Be(OH)₂**: A weak base, but it is not a salt in the context of this question.
- **FeCl₃**: Derived from iron(III) hydroxide (Fe(OH)₃, a weak base) and hydrochloric acid (HCl, a strong acid).
- **AlCl₃**: Derived from aluminum hydroxide (Al(OH)₃, a weak base) and hydrochloric acid (HCl, a strong acid).

### Step 3: Determine the Strength of the Bases
The acidity of the salt in water is influenced by the strength of the base:
- Ni(OH)₂ is a weak base.
- Fe(OH)₃ is also a weak base.
- Al(OH)₃ is a weak base, but it is known to be weaker than both Ni(OH)₂ and Fe(OH)₃.

### Step 4: Compare the Acidity
In general, the more acidic the salt, the weaker the base from which it is derived. Since all the salts are derived from a strong acid (HCl), we can conclude:
- The salt derived from the weakest base will be the most acidic.

### Step 5: Conclusion
Among the bases:
- Al(OH)₃ is the weakest base.
Thus, the salt **AlCl₃** will be the most acidic in water.

### Final Answer
**Aluminum chloride (AlCl₃) is the most acidic salt in water.**

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