Chapter 8, Problem 50A

(a)

Interpretation Introduction

Interpretation : Whether a precipitate forms when sodium sulphide aqueous solution is mixed with copper sulphate aqueous solution or not needs to be determined.

Concept Introduction : During double displacement reaction certain ionic solutions produce undissolved solid residue called precipitate.

The formation of precipitate can be predicted by using solubility rules.

Answer to Problem 50A

Calcium sulphide precipitate is formed.

Explanation of Solution

When sodium sulphide aqueous solution is mixed with copper sulphate solution, then copper sulphide precipitate is formed.

The balanced chemical equation for the given reaction is shown below:

  $CuS{O}_4(aq)+N{a}_{2}S(aq)\to CuS(s)+N{a}_{2}S{O}_4(aq)$

Net ionic equation is obtained from complete ionic equation by cancelling the spectator ions.

Complete ionic equation for the above reaction is:

  $C{u}^{2+}(aq)+S{O}_4{}^{2-}(aq)+2N{a}^{+}(aq)+S^{2-}(aq)\to CuS(s)+S{O}_4{}^{2-}(aq)+2N{a}^{+}(aq)$

Net ionic equation:

  $C{u}^{2+}(aq)+S^{2-}(aq)\to CuS(s)$

Spectator ions are sodium ions and sulphate ions.

(b)

Interpretation Introduction

Interpretation : Whether a precipitate forms when cobalt chloride solution is mixed with sodium hydroxide solution needs to be determined.

Concept Introduction : During double displacement reaction certain ionic solutions produce undissolved solid residue called precipitate.

The formation of precipitate can be predicted by using solubility rules.

Answer to Problem 50A

Cobalt hydroxide precipitate is formed.

Explanation of Solution

When cobalt chloride aqueous solution is mixed with sodium hydroxide aqueous solution, then cobalt hydroxide precipitate is formed.

The balanced chemical equation for the given reaction is shown below:

  $CoC{l}_2(aq)+2NaOH(aq)\to Co{(OH)}_2(s)+2NaCl(aq)$

Net ionic equation is obtained from complete ionic equation by cancelling the spectator ions.

Complete ionic equation for the above reaction is:

  $C{o}^{2+}(aq)+2C{l}^{-}(aq)+2N{a}^{+}(aq)+2O{H}^{-}(aq)\to Co{(OH)}_2(s)+2N{a}^{+}(aq)+2C{l}^{-}(aq)$

Net ionic equation is:

  $C{o}^{2+}(aq)+2O{H}^{-}(aq)\to Co{(OH)}_2(s)$

The spectator ions are sodium ion and chloride ion.

(c)

Interpretation Introduction

Interpretation : Whether a precipitate forms when potassium iodide solution is mixed with silver nitrate solution needs to be determined.

Concept Introduction : During double displacement reaction certain ionic solutions produce undissolved solid residue called precipitate.

The formation of precipitate can be predicted by using solubility rules.

Answer to Problem 50A

Silver iodide precipitate is formed.

Explanation of Solution

When potassium iodide aqueous solution is mixed with silver nitrate solution, then silver iodide precipitate is formed.

The balanced chemical equation for the reaction is:

  $KI(aq)+AgN{O}_3(aq)\to AgI(s)+KN{O}_3(aq)$

Net ionic equation is obtained from complete ionic equation by cancelling the spectator ions.

Complete ionic equation for the above reaction is:

  $K^{+}(aq)+I^{-}(aq)+A{g}^{+}(aq)+N{O}_3{}^{-}(aq)\to AgI(s)+K^{+}(aq)+N{O}_3{}^{-}(aq)$

Net ionic equation is:

  $A{g}^{+}(aq)+I^{-}(aq)\to AgI(s)$

The spectator ions are: potassium ion and nitrate ions.