Chapter U4, Problem 7RE

Interpretation Introduction

Interpretation: Whether the precipitate forms in the reactions from previous problem or not is to be predicted.

Concept introduction:

When two different salts solution are mixed, a cation/anion pair in the resulting solution forms an insoluble salt; this insoluble salt is termed as precipitate and this type of reaction is termed as precipitation reaction.

Answer to Problem 7RE

All the reactions from previous problem form precipitate. The reaction is shown below:

  $\begin{array}{l}\text{Mg}{\left({\text{NO}}_{\text{3}}\right)}_2\left(aq\right)+{\text{CaCl}}_{\text{2}}\left(aq\right)\to {\text{MgCl}}_{\text{2}}\left(s\right)+\left({\text{NO}}_{\text{3}}\right)\text{Ca}\left(aq\right)\\ \left(\text{precipitate}\right)\\ {\text{AgNO}}_{\text{3}}\left(aq\right)+\text{KI}\left(aq\right)\to \text{Agl}\left(s\right)+{\text{KNO}}_{\text{3}}\left(aq\right)\\ \left(\text{precipitate}\right)\\ {\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}\left(aq\right)+{\text{BaCl}}_{\text{2}}\left(aq\right)\to {\text{BaSO}}_{\text{4}}\left(s\right)+2\text{NaCl}\left(aq\right)\\ \left(\text{precipitate}\right)\end{array}$

Explanation of Solution

Magnesium nitrate reacts with calcium chloride to form precipitate of magnesium chloride and calcium nitrate. The corresponding equation is shown below:

  $\text{Mg}{\left({\text{NO}}_{\text{3}}\right)}_2\left(aq\right)+{\text{CaCl}}_{\text{2}}\left(aq\right)\to {\text{MgCl}}_{\text{2}}\left(s\right)+\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_2\left(aq\right)$

Aqueous silver nitrate reacts with potassium iodide to form precipitate of silver iodide and potassium nitrate. The corresponding equation is shown below:

  ${\text{AgNO}}_{\text{3}}\left(aq\right)+\text{KI}\left(aq\right)\to \text{Agl}\left(s\right)+{\text{KNO}}_{\text{3}}\left(aq\right)$

Aqueous sodium sulfate reacts with barium chloride to form precipitate of barium sulfate and sodium chloride. The corresponding reaction is shown below:

  ${\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}\left(aq\right)+{\text{BaCl}}_{\text{2}}\left(aq\right)\to {\text{BaSO}}_{\text{4}}\left(s\right)+2\text{NaCl}\left(aq\right)$