Question #b3525

1 Answer
Dec 15, 2014

The best way to approach such a question is by checking the solubility rules for each of the ionic compounds (more here: http://www.chem.sc.edu/faculty/morgan/resources/solubility/).

Let's start with Co(NO3)2. According to the aforementioned solubility rules, all nitrate (NO3) salts are soluble, so we would get

Co(NO3)2(aq)Co2+(aq)+2NO3(aq)

This means that the concentrations of Co2+ and NO3 will be

0.50molesCo(NO3)21Lsolution1moleCo2+1moleCo(NO3)2=0.50M Co2+

0.50molesCo(NO3)21Lsolution2molesNO31moleCo(NO3)2=1.0M NO3

Notice that the NO3's concentration will be twice as big as the concentration of Co(NO3)2, since 2 moles of the former are produced for every 1 mole of the latter.

Moving on to Fe(ClO4)3. The solubility rules tell us that all perchlorate (ClO4) salts are soluble, so we will get

Fe(ClO4)3(aq)Fe3+(aq)+3ClO4(aq)

Therefore, the concentrations of the two ions will be

1moleFe(ClO4)31Lsolution1moleFe3+1moleFe(ClO4)3=1M Fe3+

1moleFe(ClO4)31Lsolution3molesClO41moleFe(ClO4)3=3M ClO4