Question

Given the balanced ionic equation representing a reaction:

Answer 1

The answer is (3) Mg to Al3+. The Mg(s) changes to Mg2+ and lose electrons. Al3+ changes to Al(s) and gain electrons. So the electrons transferred from Mg to Al3+. 

Answer 2

Answer:

3) Mg to Al3+

Explanation:

The given reaction is:

$2Al^{3+} (aq) + 3Mg(s) ---- 3Mg^{2+} (aq) + 2Al(s)$

This is an example of a redox reaction i.e. a reduction-oxidation reaction which involves transfer of electrons between Al and Mg.

Reduction involves gain of electrons, whereas oxidation involves loss of electrons. The two half reactions can be depicted as shown below:

Oxidation:

$Mg(s) ----- Mg^{2+} + 2e-$

Reduction:

$Al^{3+} (aq) + 3e- ---- Al(s)$

Thus Mg loses electrons and gets oxidised to Mg2+

whereas Al3+ gains electrons and gets reduced to Al3+