Question

Choose a chemical equation for the reaction that will occur, if any, when: (If no reaction will occur, choose “no reaction”.) aluminum metal is added to a solution of copper(II) chloride a) 3Al(s) + 2 Cu 2+(aq) → 3Al3+(aq) + Cu (s)

b) Al(s) + Cu 2+(aq) → Al3+(aq) + Cu (s)

c) no reaction

d) 2Al(s) + 3 Cu 2+(aq) → 2Al3+(aq) + 3 Cu (s)

mercury metal is added to a solution of magnesium sulfate.

a) 2 Hg (s) + 3Mg2+(aq) → 2 Hg 2+(aq) + 3Mg(s)

b) 2 Hg (s) + 3Mg2+(aq) → 2 Hg 3+(aq) + 3Mg(s)

c) 2 Hg (s) + 3Mg2+(aq) → 2 Hg +(aq) + 3Mg(s)

d) no reaction

Please explain how this is done

Answer 1

aluminum metal is added to a solution of copper(II) chloride

Al(s) + Cu+2 + 2Cl-(aq)...

review potentials

Cu2+ + 2 e− ⇌ Cu(s) +0.337

Al3+ + 3 e− ⇌ Al(s) −1.662

clearly, Coppper will reduce, due to its potential

so

expect Cu+2 to convert to Cu(s)

so:

Al(s) + Cu+2(aq) + 2Cl-(aq) --> Cu(s) + Al3+(aq) + 2Cl-(aq)

balance:

2Al(s) + 3Cu+2(aq) + 6Cl-(aq) --> 3Cu(s) + 2Al3+(aq) + 6Cl-(aq)

net ionic

2Al(s) + 3Cu+2(aq) --> 3Cu(s) + 2Al3+(aq)

mercury metal is added to a solution of magnesium sulfate.

Hg(s) + MgSO4(aq)

in solution:

Hg(s) + Mg+2(aq) + SO4-2(aq)

we need to review potentials:

Mg2+ + 2 e− ⇌ Mg(s) −2.372

Hg22+ + 2 e− ⇌ 2 Hg(l) +0.80

clearly, Mg+2 has the lowest potential, so expect NO REACTION