In cation exchange process for removing hardness of water, the resulting water turns

Options

A. Acidic
B. Basic
C. Neutral
D. Both 1 and 2

Answer

To solve the question regarding the cation exchange process for removing hardness of water, let's break it down step by step:

### Step 1: Understanding Hard Water
Hard water contains high concentrations of certain cations, primarily calcium (Ca²⁺) and magnesium (Mg²⁺) ions. These ions are responsible for the hardness of water, which can cause scaling and reduce the effectiveness of soaps.

**Hint:** Identify the ions responsible for water hardness.

### Step 2: Cation Exchange Process
The cation exchange process involves passing hard water through a cation exchange resin. This resin is typically made of large organic molecules that contain sulfonic acid groups (–SO₃H). The resin can exchange its hydrogen ions (H⁺) for the cations in the water.

**Hint:** Remember the role of the cation exchange resin in the process.

### Step 3: Ion Exchange Reaction
As hard water passes through the cation exchange resin, the calcium and magnesium ions are replaced by hydrogen ions from the resin. The reaction can be summarized as:
- Ca²⁺ or Mg²⁺ ions in the water are exchanged for H⁺ ions from the resin.

**Hint:** Focus on the exchange of ions that occurs during the process.

### Step 4: Resulting Water Composition
After the cation exchange process, the resulting water will have a higher concentration of hydrogen ions (H⁺) compared to the original hard water. This increase in H⁺ ions leads to a decrease in pH, making the water acidic.

**Hint:** Consider how the concentration of H⁺ ions affects the acidity of the water.

### Step 5: Conclusion
Therefore, the resulting water after the cation exchange process for removing hardness turns acidic.

**Final Answer:** The correct option is **acidic**.

### Summary of Steps:
1. Identify the ions causing hardness (Ca²⁺ and Mg²⁺).
2. Understand the role of cation exchange resin.
3. Recognize the ion exchange reaction (H⁺ replaces Ca²⁺ and Mg²⁺).
4. Determine the effect on water pH (increased H⁺ makes it acidic).
5. Conclude that the resulting water is acidic.