D is a green crystalline solid that dissolves in water to give a very pale green solution. Addition of sodium hydroxide solution to a solution of D
produces a green precipitate, E, which turns orange-brown around the top
after standing in air. Addition of dilute hydrochloric acid and barium chloride
solution to a solution of D gives a white precipitate, F.
a State the names of D, E and F.

See below.

Explanation:

a. D is ferrous sulphate FeSO4 or it can be called Iron(II) Sulphate.

E is Ferric hydroxide. or Iron(III) hydroxide

F. Barium sulphate. BaSO4

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.

if it's not useful, feel free to report for mistake in answer.

answer seismograph;