Chapter 8, Problem 41A

Solution

Interpretation: Three reagents which can form precipitate with chloride ion, calcium ion, iron (III) ion, sulfate ion, mercury(I) ion and silver ion needs to be determined. The net ionic equation needs to be determined.

Concept introduction: Some cations and anions combine in aqueous solution to form insoluble solid products called precipitates.

Chloride ion can be precipitated using silver nitrate, lead nitrate and mercury (I) nitrate.

Calcium ion can be precipitated using dilute sulphuric acid, ammonium carbonate and ammonium oxalate.

Iron (III) ion can be precipitated using ammonium hydroxide, hydrogen sulfide and potassium ferrocyanide.

Sulfate ion can be precipitated using barium chloride, silver nitrate and lead acetate.

Mercury (I) ion can be precipitated using dilute hydrochloric acid, sodium hydroxide and ammonium hydroxide.

Silver ion can be precipitated using dilute hydrochloric acid, potassium bromide and potassium iodide solution.

Precipitation takes place when the salts formed by the combination ions are insoluble in water.

Precipitation of chloride by silver nitrate can be represented as,

  ${\text{Cl}}_{(aq)}^{-}{\text{ + Ag}}_{(aq)}^{+}\to {\text{ AgCl}}_{(s)}$

Precipitation of chloride by lead nitrate can be represented as,

  ${\text{2Cl}}_{(aq)}^{-}{\text{ + Pb}}_{(aq)}^{2+}\to {\text{ PbCl}}_{2(s)}$

Precipitation of chloride by mercury (I) nitrate can be represented as,

  ${\text{2Cl}}_{(aq)}^{-}{\text{ + Hg}}_{2(aq)}^{2+}\to {\text{ Hg}}_2{\text{Cl}}_{2(s)}$

Precipitation of calcium ion by dilute sulphuric acid can be represented as,

  ${\text{Ca}}_{(aq)}^{2+}{\text{ + SO}}_4{}_{(aq)}^{2-}\to {\text{ CaSO}}_4{}_{(s)}$

Precipitation of calcium ion by ammonium carbonate can be represented as,

  ${\text{Ca}}_{(aq)}^{2+}{\text{ + CO}}_3{}_{(aq)}^{2-}\to {\text{ CaCO}}_3{}_{(s)}$

Precipitation of calcium ion by ammonium oxalate can be represented as,

  ${\text{Ca}}_{(aq)}^{2+}{\text{ + C}}_2{\text{O}}_4{}_{(aq)}^{2-}\to {\text{ CaC}}_2{\text{O}}_4{}_{(s)}$

Precipitation of iron (III) ion by ammonium hydroxide can be represented as,

  ${\text{Fe}}_{(aq)}^{3+}{\text{ + 3OH}}_{(aq)}^{-}\to {\text{ Fe(OH)}}_3{}_{(s)}$

Precipitation of iron (III) ion by hydrogen sulfide can be represented as,

  ${\text{2Fe}}_{(aq)}^{3+}{\text{ + 3S}}_{(aq)}^{2-}\to {\text{ Fe}}_2{\text{S}}_3{}_{(s)}$

Precipitation of iron (III) ion by potassium ferrocyanide can be represented as,

  ${\text{4Fe}}_{(aq)}^{3+}{\text{ + 3Fe(CN)}}_6{}_{(aq)}^{4-}\to {\text{ Fe}}_4{{\text{[Fe(CN}}_6\text{)]}}_3{}_{(s)}$

Precipitation of Sulfate ion by barium chloride can be represented as,

  ${\text{SO}}_{4(aq)}^{2-}{\text{ + Ba}}_{(aq)}^{2+}\to {\text{ BaSO}}_{4(s)}$

Precipitation of Sulfate ion by silver nitrate can be represented as,

  ${\text{SO}}_{4(aq)}^{2-}{\text{ + 2Ag}}_{(aq)}^{+}\to {\text{ Ag}}_2{\text{SO}}_{4(s)}$

Precipitation of Sulfate ion by lead acetate can be represented as,

  ${\text{SO}}_{4(aq)}^{2-}{\text{ + Pb}}_{(aq)}^{2+}\to {\text{ PbSO}}_{4(s)}$

Precipitation of mercury (I) ion by dilute hydrochloric acid can be represented as,

  ${\text{Hg}}_{2(aq)}^{2+}{\text{+ 2Cl}}_{(aq)}^{-}\to {\text{ Hg}}_2{\text{Cl}}_{2(s)}$

Precipitation of mercury (I) ion by sodium hydroxide can be represented as,

  ${\text{Hg}}_{2(aq)}^{2+}{\text{+ 2OH}}_{(aq)}^{-}\to {\text{ Hg}}_{(l)}{\text{+HgO}}_{(s)}{\text{+H}}_2{\text{O}}_{(l)}$

Precipitation of mercury (I) ion by ammonium hydroxide can be represented as,

  ${\text{Hg}}_{2(aq)}^{2+}{\text{+ 2NH}}_4{\text{OH}}_{(aq)}\to {\text{ Hg(NH}}_2{\text{)Cl}}_{(s)}{\text{+ Hg}}_{(l)}{\text{ + NH}}_4{\text{Cl}}_{(aq)}{\text{ +H}}_2{\text{O}}_{(l)}$

Precipitation of silver ion by dilute hydrochloric acid can be represented as,

  ${\text{Ag}}_{(aq)}^{+}{\text{+ Cl}}_{(aq)}^{-}\to {\text{ AgCl}}_{(s)}$

Precipitation of silver ion by potassium bromide can be represented as,

  ${\text{Ag}}_{(aq)}^{+}{\text{+ Br}}_{(aq)}^{-}\to {\text{ AgBr}}_{(s)}$

Precipitation of silver ion by potassium iodide can be represented as,

  ${\text{Ag}}_{(aq)}^{+}{\text{+ I}}_{(aq)}^{-}\to {\text{ AgI}}_{(s)}$

Thus, chloride ion can be precipitated using silver nitrate, lead nitrate and mercury (I) nitrate.

Calcium ion can be precipitated using dilute sulphuric acid, ammonium carbonate and ammonium oxalate.

Iron (III) ion can be precipitated using ammonium hydroxide, hydrogen sulfide and potassium ferrocyanide.

Sulfate ion can be precipitated using barium chloride, silver nitrate and lead acetate.

Mercury (I) ion can be precipitated using dilute hydrochloric acid, sodium hydroxide and ammonium hydroxide.

Silver ion can be precipitated using dilute hydrochloric acid, potassium bromide and potassium iodide solution.