Chemistry questions?

1)
Assume that inert electrodes are used.

Copper(II) and hydrogen ions migrate to the cathode. Copper(II) ion is preferentially discharged to be reduced (gaining electrons) to copper atom because the concentration of copper(II) ions is higher than that of hydrogen ions.
• A is false.
• D is true.

Bromide and hydroxide ions migrate to the anode. Bromide(II) ion is preferentially discharged to be oxidized (losing electrons) to bromine molecules because the concentration of bromide ions is higher than that of hydroxide ions.
• B is false.
• C is false. (Bromine molecules are formed, but NOT bromide molecules.)

The answer: D- copper ions gain electrons to form copper atoms


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2)
XCl has high boiling point and is soluble in water. It can be deduced that XCl is an ionic compound.

Cl⁻ ion carries a negative charge. Due to XCl is a neutral compound, the ion of K must carry a positive charge, i.e. X⁺. It can be deduced that element X belongs to Group I of the periodic table.

Electrochemistry ... etc.

There are two possible reduction reactions which can occur at the cathode:
Cu2+ + 2e- --> Cu(s) ..................... E = +0.34V
2H2O(l) + 2e- --> H2(g) + 2OH- ..... E = -0.83V
The reaction of copper(II) ions forming copper metal is more favorable. That is why (D) is the answer.

As for (2), you know from the high melting and boiling points and the water solubility that XCl is a water soluble salt and that X has an oxidation state of +1. It is highly likely that X is an alkali metal (group 1) since other metals with an oxidation state of +1 often form insoluble chlorides or have much lower melting and boiling points, or both. Examples: TlCl, AuCl, AgCl, Hg2Cl2, etc.