Permanent hardness in water due to presence of :

Options

A. `Ca^(+),Mg^(+)`
B. `CaCl_(2),MgCl_(2)`
C. `CaCO_(3),MgCO_(3)`
D. All

Answer

To determine the cause of permanent hardness in water, let's analyze the options provided step by step.

### Step 1: Understand Permanent Hardness
Permanent hardness in water is defined as the hardness that cannot be removed by boiling. It is primarily due to the presence of certain mineral salts.

### Step 2: Identify Causes of Permanent Hardness
Permanent hardness is mainly caused by the presence of:
- Chlorides
- Sulfates
- Other heavy metal ions such as calcium, magnesium, and iron.

### Step 3: Analyze the Options
1. **Calcium and Magnesium Ions**: These ions are indeed responsible for hardness in water, but they can be present in both temporary and permanent hardness.

2. **Calcium Chloride and Magnesium Chloride**: These compounds are specifically associated with permanent hardness because they are soluble salts that do not precipitate out upon boiling.

3. **Calcium Carbonate and Magnesium Carbonate**: These compounds can contribute to temporary hardness because they can precipitate out when heated, thus removable by boiling.

4. **All of the Above**: This option suggests that all the previous options contribute to permanent hardness, which is incorrect since not all of them do.

### Step 4: Conclusion
Based on the analysis, the correct answer is **Calcium Chloride and Magnesium Chloride**, as they are the primary contributors to permanent hardness in water.

### Final Answer
The correct option is **Calcium Chloride and Magnesium Chloride**.

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