When a sample of hard water is passed through the layer of sodium zeolite resulting which of the following ions will not be present in the resulting sample of water obtained?

Options

A. `Mg^(2+)` and `Ca^(2+)`
B. `Ca^(2+)` and `Na^(o+)`
C. `Mg^(2+)` and `CO_(3)^(2-)`
D. `CO_(3)^(2-)` and `Cl^(ɵ)`

Explanation

To solve the question regarding the ions that will not be present in the resulting sample of water after passing hard water through sodium zeolite, we can follow these steps:

### Step 1: Understand the Composition of Hard Water
Hard water contains dissolved minerals, primarily calcium ions (Ca²⁺) and magnesium ions (Mg²⁺), which contribute to its hardness.

**Hint:** Remember that hard water is characterized by the presence of specific ions that cause its hardness.

### Step 2: Know the Function of Sodium Zeolite
Sodium zeolite is a cation exchange resin that is used to soften hard water. It contains sodium ions (Na⁺) and can exchange these sodium ions with the hardness-causing ions in the water.

**Hint:** Cation exchange means that one type of ion is replaced by another, so focus on what ions are exchanged.

### Step 3: The Cation Exchange Process
When hard water passes through sodium zeolite, the calcium (Ca²⁺) and magnesium (Mg²⁺) ions are exchanged for sodium ions (Na⁺). The chemical reactions can be summarized as follows:
- Ca²⁺ (from hard water) + Na₂Z (sodium zeolite) → CaZ + 2Na⁺
- Mg²⁺ (from hard water) + Na₂Z (sodium zeolite) → MgZ + 2Na⁺

This means that the hardness-causing ions (Ca²⁺ and Mg²⁺) are removed from the water.

**Hint:** Identify which ions are being replaced and which ones remain in the water after the exchange.

### Step 4: Identify the Ions Present After Treatment
After the treatment with sodium zeolite, the resulting water sample will have sodium ions (Na⁺) in place of the calcium and magnesium ions. Therefore, the ions that will not be present in the resulting sample of water are the hardness-causing ions: calcium (Ca²⁺) and magnesium (Mg²⁺).

**Hint:** Focus on the ions that were originally present in hard water and are removed during the softening process.

### Conclusion
The ions that will not be present in the resulting sample of water obtained after passing hard water through sodium zeolite are calcium ions (Ca²⁺) and magnesium ions (Mg²⁺).

**Final Answer:** Calcium (Ca²⁺) and Magnesium (Mg²⁺) ions will not be present in the resulting sample of water.