Consider the following half-cell reactions.
Al(s) \(\to\) Al3+(aq) + 3e-
Cu2+(aq) + 2e- \(\to\) Cu(s)
The overall equation for the reaction is
A.
Al(s) + Cu2+(aq) \(\to\) Al3+(aq) + Cu(s)
B.
2Al(s) + Cu2+(aq) \(\to\) 2Al(aq) + Cu(s)
C.
2Al(s) + 3Cu2+(aq) \(\to\) 3Cu(s) + 2Al3+(aq)
D.
3Al(s) + 2Cu2+(aq) \(\to\) Cu(s) + 3Al3+(aq)
Correct answer is C
Al(s) \(\to\) Al3+(aq) + 3e- ______(i)
Cu2+(aq) + 2e- \(\to\) Cu(s) ________(ii)
To balance the electrons, multiply equation (i) by 2 and equation (ii) by 3 and then add the resulting equations
2Al(s) \(\to\)2Al3+(aq) + 3e-
3cu2+(aq) + 6e- \(\to\)3Cu(s)
2Al(s) + 3Cu2+(aq) \(\to\) 3Cu(s) + 2Al3+(aq)
