Why does tap water reach a higher temperature than distilled water when exposed to the same microwave radiation power?

Question

А.
Tap water has a lower specific heat capacity.
Tap water contains dissolved substances and impurities, enhancing energy absorption.
С.
D.
Distilled water absorbs microwaves more efficiently than tap water.
There is no difference in heating between tap water and distilled water.

Answer 1

The correct answer is:

Tap water contains dissolved substances and impurities, enhancing energy absorption.

Tap water often contains minerals, salts, and other impurities that can absorb microwave radiation more effectively than pure distilled water. These dissolved substances can contribute to changes in the heat capacity and thermal conductivity of the water, allowing it to reach a higher temperature under the same microwave radiation conditions. Distilled water, being purer and having fewer dissolved species, may have a slightly different heating profile when microwaved.