Which of the following properties show a reverse trend in moving down the group of alkali and alkaline earth metals?

Options

A. Solubility of hydroxides
B. Solubility of carbonates
C. Solubility of sulphates
D. Solubility of oxides

Answer

To determine which properties show a reverse trend when moving down the group of alkali and alkaline earth metals, we will analyze the solubility trends of hydroxides, carbonates, sulfates, and oxides for both groups.

### Step-by-Step Solution:

1. **Identify the Properties to Analyze**:
We need to analyze the following properties:
- Solubility of Hydroxides
- Solubility of Carbonates
- Solubility of Sulfates
- Solubility of Oxides

2. **Analyze the Solubility of Hydroxides**:
- For alkali metals (Group 1), the solubility of hydroxides increases down the group (LiOH < NaOH < KOH < RbOH < CsOH).
- For alkaline earth metals (Group 2), the solubility of hydroxides also increases down the group (Mg(OH)₂ < Ca(OH)₂ < Sr(OH)₂ < Ba(OH)₂).
- **Conclusion**: Both groups show the same trend (increase), so this property does not show a reverse trend.

3. **Analyze the Solubility of Carbonates**:
- For alkali metals, the solubility of carbonates increases down the group (Li₂CO₃ < Na₂CO₃ < K₂CO₃ < Rb₂CO₃ < Cs₂CO₃).
- For alkaline earth metals, the solubility of carbonates decreases down the group (CaCO₃ > SrCO₃ > BaCO₃).
- **Conclusion**: This property shows a reverse trend (alkali metals increase, alkaline earth metals decrease).

4. **Analyze the Solubility of Sulfates**:
- For alkali metals, the solubility of sulfates increases down the group (Li₂SO₄ < Na₂SO₄ < K₂SO₄ < Rb₂SO₄ < Cs₂SO₄).
- For alkaline earth metals, the solubility of sulfates decreases down the group (CaSO₄ > SrSO₄ > BaSO₄).
- **Conclusion**: This property also shows a reverse trend (alkali metals increase, alkaline earth metals decrease).

5. **Analyze the Solubility of Oxides**:
- For alkali metals, the solubility of oxides increases down the group (Li₂O < Na₂O < K₂O < Rb₂O < Cs₂O).
- For alkaline earth metals, the solubility of oxides also increases down the group (MgO < CaO < SrO < BaO).
- **Conclusion**: Both groups show the same trend (increase), so this property does not show a reverse trend.

### Final Answer:
The properties that show a reverse trend when moving down the group of alkali and alkaline earth metals are:
- **B. Solubility of Carbonates**
- **C. Solubility of Sulfates**