Question

For each of the following aqueous mixtures, determine
which ionic concentrations decrease and which remain the
same.
a. Sodium chloride and iron(II) chloride are dissolved in
100 mL water.
b. Equimolar amounts of sodium carbonate and sulfuric
acid react.
c. Potassium sulfate and barium nitrate are dissolved in
100 mL water.

Answer 1

1) ionic concentration is the concentration of ions in a solution

(a) when NaCl and FeCl3 are dissoved in water then they will undergo dissociation as

NaCL --> Na+   + Cl-

FeCL3 --> Fe+3 + 3Cl-

So due to common ion effect the ionic concentration will decrease

(b) When equimolar amounts of sodium carbonate and sulphuric acid react they neutralize each other

So the ionic concentration will decrease

(c) Potassium sulfate and barium nitrate are dissolved in
100 mL water.

They wil dissociate independant of each other and will furnish ions so the ionic concentration will increase.