Question

Give an example how each of the following insoluble ionic compounds could be produced using a precipitation reaction. Write the balanced formula equation for each reaction. a. \(\mathrm{Fe}(\mathrm{OH})_{3}(s)\) b. \(\mathrm{Hg}_{2} \mathrm{Cl}_{2}(s)\) c. \(\mathrm{PbSO}_{4}(s)\) d. \(\mathrm{BaCrO}_{4}(s)\)

Short answer

a. Iron (III) hydroxide: \[2\mathrm{Fe(NO}_3)_3(aq) + 6\mathrm{NaOH}(aq) \rightarrow 2\mathrm{Fe(OH)}_3(s) + 6\mathrm{NaNO_3}(aq)\] b. Mercury (I) chloride: \[\mathrm{Hg_2(NO}_3)_2(aq) + 2\mathrm{NaCl}(aq) \rightarrow \mathrm{Hg_2Cl_2}(s) + 2\mathrm{NaNO_3}(aq)\] c. Lead (II) sulfate: \[\mathrm{Pb(NO}_3)_2(aq) + \mathrm{Na_2SO}_4(aq) \rightarrow \mathrm{PbSO}_4(s) + 2\mathrm{NaNO_3}(aq)\] d. Barium chromate: \[\mathrm{Ba(NO}_3)_2(aq) + \mathrm{K_2CrO}_4(aq) \rightarrow \mathrm{BaCrO}_4(s) + 2\mathrm{KNO_3}(aq)\]

Step-by-step solution

a. Formation of Iron (III) Hydroxide, \(\mathrm{Fe}(\mathrm{OH})_{3}(s)\)

To form \(\mathrm{Fe}(\mathrm{OH})_{3}(s)\), we can mix a soluble iron (III) compound, such as iron (III) nitrate, \(\mathrm{Fe(NO}_3)_3(aq)\), and a soluble hydroxide compound, such as sodium hydroxide, \(\mathrm{NaOH}(aq)\). The balanced equation for this precipitation reaction is: \[2\mathrm{Fe(NO}_3)_3(aq) + 6\mathrm{NaOH}(aq) \rightarrow 2\mathrm{Fe(OH)}_3(s) + 6\mathrm{NaNO_3}(aq)\]

b. Formation of Mercury (I) Chloride, \(\mathrm{Hg}_{2} \mathrm{Cl}_{2}(s)\)

To form \(\mathrm{Hg}_{2}\mathrm{Cl}_{2}(s)\), we can mix a soluble mercury (I) compound, such as mercury (I) nitrate, \(\mathrm{Hg_2(NO}_3)_2(aq)\), and a soluble chloride compound, such as sodium chloride, \(\mathrm{NaCl}(aq)\). The balanced equation for this precipitation reaction is: \[\mathrm{Hg_2(NO}_3)_2(aq) + 2\mathrm{NaCl}(aq) \rightarrow \mathrm{Hg_2Cl_2}(s) + 2\mathrm{NaNO_3}(aq)\]

c. Formation of Lead (II) Sulfate, \(\mathrm{PbSO}_{4}(s)\)

To form \(\mathrm{PbSO}_4(s)\), we can mix a soluble lead (II) compound, such as lead (II) nitrate, \(\mathrm{Pb(NO}_3)_2(aq)\), and a soluble sulfate compound, such as sodium sulfate, \(\mathrm{Na_2SO}_4(aq)\). The balanced equation for this precipitation reaction is: \[\mathrm{Pb(NO}_3)_2(aq) + \mathrm{Na_2SO}_4(aq) \rightarrow \mathrm{PbSO}_4(s) + 2\mathrm{NaNO_3}(aq)\]

d. Formation of Barium Chromate, \(\mathrm{BaCrO}_{4}(s)\)

To form \(\mathrm{BaCrO}_4(s)\), we can mix a soluble barium compound, such as barium nitrate, \(\mathrm{Ba(NO}_3)_2(aq)\), and a soluble chromate compound, such as potassium chromate, \(\mathrm{K_2CrO}_4(aq)\). The balanced equation for this precipitation reaction is: \[\mathrm{Ba(NO}_3)_2(aq) + \mathrm{K_2CrO}_4(aq) \rightarrow \mathrm{BaCrO}_4(s) + 2\mathrm{KNO_3}(aq)\]