Which of the following statements is false about hard water?

Answer Details

Hard water contains dissolved calcium and magnesium ions (Ca²⁺ and Mg²⁺). Several properties of hard water are well established:

• The calcium ions help build strong teeth and bones in animals - this is a genuine advantage of hard water.
• Hard water tastes better than soft water because of its mineral content - this is widely accepted.
• Hard water can actually be safely supplied through lead pipes. The dissolved calcium and magnesium salts react with lead to form insoluble compounds (such as lead carbonate) that coat the inside of the pipe, creating a protective lining. This prevents further lead from dissolving into the water. In contrast, soft water in lead pipes is dangerous because it can dissolve lead, causing lead poisoning.

The statement that hard water cannot be supplied in pipes made of lead is false. The opposite is true: hard water is safer in lead pipes than soft water, precisely because the mineral deposits form a barrier that prevents lead contamination.