Question

Why does fur form inside a kettle in which water has been boiled for a long time? Give the chemical names and formulae of this fur? In what way is it a nuisance?

Answer 1

Repeated boiling of hard water leads to the deposition of insoluble material called fur or scale.
The chemical name of this fur is calcium carbonate (CaCO₃) or magnesium carbonate (MgCO₃).
It is a nuisance as it may coat the heating element in kettles, making them less efficient. As a result, it takes extra time for water to get boiled in such vessels. Also, this fur or insoluble calcium carbonate is unpleasant and it clogs up hot water pipes and boilers.