Question

Rain water does not leave behind concentric rings when boiled.
(A) True
(B) False

Answer 1

Hint: The presence of dissolved solids in water promotes the formation of concentric rings when boiled. Rainwater is typically devoid of all dissolved solids but contains dissolved gases (oxides of carbon, nitrogen and sulphur).

Complete step by step solution:
Rainwater is a mixed electrolyte that contains varying amounts of major and minor ions and is typically devoid of all dissolved solids. The presence of dissolved solids promotes the formation of concentric rings. As rainwater does not contain any dissolved solids, so it will not leave behind concentric rings on boiling.
Rainwater does not leave behind concentric rings when boiled, hence the correct option will be option (A); true.

Note:
Sodium, potassium, magnesium, calcium, chloride, bicarbonate and sulfate ions are the major constituents of rainwater. Because of the absence of dissolved solids, it does not form concentric rings when boiled. However, in coastal areas, rainwater may also contain up to $ 15 $ $ mg/l $ of sodium chloride from sea-spray. So, sea water may form concentric rings when boiled.