A student was given four unknown solutions each was checked for conductivity and tested with phenolphthalein the results below
Based on data in table which unknown solution could be 0.1M NaOH

The solution which could be with 0.1 M NaOH is solution "C"

Explanation:

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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