Question

Temporary hardness of water is caused by :
A. Chlorides
B. Sulfates
C. Carbonates
D. Bi-carbonates
E. Sodium and Potassium
Choose the correct answer.

• A. C, D only
• B. A, B, E only
• C. A, B, C only
• D. A, D, B only

Hint:

Temporary hardness = removable by boiling = bicarbonates.

Answer 1

The Correct Option is A

Concept: Water hardness is due to dissolved salts of calcium and magnesium.

Step 1: Temporary hardness.

• Caused by carbonates and bicarbonates of calcium and magnesium
• Removed by boiling

Step 2: Permanent hardness.

• Caused by chlorides and sulfates
• Not removed by boiling

Step 3: Role of sodium/potassium.

• Do not contribute to hardness

Step 4: Conclusion.
Correct answer: Carbonates and bicarbonates.