Please help me answer this question

Electrolytes are observed by conductivity - so unknown 2 should be circled, and Tap Water, which almost always contains electrolytes, mineral salts in solution.

Explanation:

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metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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