Which among the following is the strongest base?

Options

A. `Be(OH)_(2)`
B. `Mg(OH)_(2)`
C. `Ba(OH)_(2)`
D. `Sr(OH)_(2)`

Answer

To determine which among the given hydroxides is the strongest base, we can follow these steps:

### Step 1: Identify the Compounds
The compounds given are:
1. Be(OH)₂ (Beryllium hydroxide)
2. Mg(OH)₂ (Magnesium hydroxide)
3. Ba(OH)₂ (Barium hydroxide)
4. Sr(OH)₂ (Strontium hydroxide)

### Step 2: Understand Basicity
Basicity refers to the ability of a compound to donate hydroxide ions (OH⁻) in solution. The stronger the base, the more readily it donates hydroxide ions.

### Step 3: Analyze the Group
All the compounds are hydroxides of alkaline earth metals (Group 2 elements). The trend in basicity for these hydroxides generally increases as we move down the group from beryllium to barium.

### Step 4: Consider Atomic Size and Nuclear Charge
As we move down the group:
- The atomic size increases due to the addition of electron shells.
- The effective nuclear charge experienced by the outermost electrons decreases because the inner shells shield the outer electrons from the nucleus.

### Step 5: Determine the Tendency to Lose Electrons
With an increase in atomic size and a decrease in effective nuclear charge, the outer electrons become less tightly bound to the nucleus. This leads to:
- An increased tendency to lose electrons.
- A higher basic character.

### Step 6: Compare the Hydroxides
Based on the trend:
- Beryllium hydroxide (Be(OH)₂) is the least basic.
- Magnesium hydroxide (Mg(OH)₂) is more basic than beryllium hydroxide.
- Strontium hydroxide (Sr(OH)₂) is more basic than magnesium hydroxide.
- Barium hydroxide (Ba(OH)₂) is the most basic among them.

### Conclusion
Thus, the strongest base among the given options is **Ba(OH)₂ (Barium hydroxide)**.

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