This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Temporary hardness of water is due to presence of: 
Select and explain. 
A. Calcium bicarbonate, B. Magnesium sulphate, C. Calcium sulphate, D. Calcium nitrate
A: Calcium bicarbonate
Answer: A: Calcium bicarbonate 
Explanation: Hardness of water is classified as carbonate or non carbonate. The carbonate hardness is also known as temporary hardness. It is caused due to presence of calcium and magnesium bicarbonate. The non carbonate hardness is also known as permanent hardness. It is caused by calcium and magnesium sulphates, chlorides and nitrates. Ref: Park 21st edition, page: 671.