Chapter 17, Problem 78GQ

(a)

Interpretation Introduction

Interpretation: Write balanced chemical equation for the given reactions and also predict whether precipitate will form or not.

  ${\text{Na}}_2{\text{SO}}_4\left(\text{aq}\right)+\text{Mg}{\left({\text{NO}}_{\text{3}}\right)}_2\left(\text{aq}\right)$

Concept introduction: Precipitation reaction takes place when anions and caations present in the solution combine to form insoluble salt. The salt will be soluble or insoluble depends upon the $K_{\text{sp}}$ value of the salt. Higher the $K_{\text{sp}}$ value soluble will be the salt. Salts having lower $K_{\text{sp}}$ value are insoluble or dissolve very less in water.

Generally,

• Sulphates are soluble except formed by ${\text{Ca}}^{2+}$, ${\text{Sr}}^{\text{2+}}$ and ${\text{Ba}}^{\text{2+}}$.
• Phosphates are insoluble.
• Chlorides, bromides, iodides are soluble except that of ${\text{Ag}}^{+}$, ${\text{Pb}}^{\text{2+}}$ and ${\text{Hg}}_{\text{2}}{}^{\text{2+}}$.
• Nitrates are soluble.

(b)

Interpretation Introduction

Interpretation: Write balanced chemical equation for the given reactions and also predict whether precipitate will form or not.

  ${\text{K}}_3{\text{PO}}_4\left(\text{aq}\right)+{\text{FeCl}}_{\text{3}}\left(\text{aq}\right)$

Concept introduction: Precipitation reaction takes place when anions and caations present in the solution combine to form insoluble salt. The salt will be soluble or insoluble depends upon the $K_{\text{sp}}$ value of the salt. Higher the $K_{\text{sp}}$ value soluble will be the salt. Salts having lower $K_{\text{sp}}$ value are insoluble or dissolve very less in water.

Generally,

• Sulphates are soluble except formed by ${\text{Ca}}^{2+}$, ${\text{Sr}}^{\text{2+}}$ and ${\text{Ba}}^{\text{2+}}$.
• Phosphates are insoluble.
• Chlorides, bromides, iodides are soluble except that of ${\text{Ag}}^{+}$, ${\text{Pb}}^{\text{2+}}$ and ${\text{Hg}}_{\text{2}}{}^{\text{2+}}$.
• Nitrates are soluble.