Chapter 3, Problem 75GQ

You are given mixtures containing the following compounds. Which compound in each pair could be separated by stirring the solid mixture with water?

(a) NaOH and Ca(OH)₂

(b) MgC1₂ and MgF₂

(c) AgI and KI

(d) NH₄Cl and PbCl₂

Interpretation Introduction

Interpretation:

The mixture containing $\text{NaOH}$ and $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$, the compound which is separated by stirring the solid mixture with water should be identified.

Concept introduction:

Most of the ionic compounds are soluble in water, very few of the ionic compounds are sparingly soluble, and some of the ionic compounds are insoluble in water.  When it is soluble in water ions gets separated in the solution.

Soluble compounds in water

Almost all the salts of ${\text{Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, NH}}_{\text{4}}{}^{\text{+}}\text{,}\left({\text{NO}}_{\text{3}}{}^{\text{-}}\right)\text{,}\left({\text{ClO}}_{\text{3}}{}^{\text{-}}\right)\text{,}\left({\text{ClO}}_{\text{4}}{}^{\text{-}}\right)\text{and}\left({\text{CH}}_{\text{3}}{\text{CO}}_{\text{2}}{}^{\text{-}}\right)$ are soluble.

Almost all the salts of ${\text{Cl}}^{\text{-}}{\text{, Br}}^{\text{-}}{\text{, I}}^{\text{-}}\left(\text{halides}\right)$ are soluble. But some of the halides $\left({\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}\right)$ are insoluble.

Salts of F^- are soluble. But some of the fluoride salt of ${\text{Mg}}^{\text{2+}}{\text{, Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble.

Salts of $\text{sulfate }\left({\text{SO}}_{\text{4}}{}^{\text{2-}}\right)$ are soluble.  But sulfates of ${\text{Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}{\text{, Ag}}^{\text{+}}\text{,}$ are insoluble.

Insoluble compounds in water:

Most of the salts of $\left({\text{CO}}_{\text{3}}{}^{\text{2-}}\right)\text{,}\left({\text{PO}}_{\text{4}}{}^{\text{3-}}\right)\text{,}\left({\text{C}}_{\text{2}}{\text{O}}_{\text{4}}{}^{\text{2-}}\right)\text{,}\left({\text{CrO}}_{\text{4}}{}^{\text{2-}}\right)\text{ and}\left({\text{S}}^{\text{2-}}\right)$ are insoluble but some of the salts of NH₄⁺, alkali metal cations and $\text{BaS}$ are soluble.

Most of the metal hydroxides and oxides are insoluble in water bit some of the alkali metal hydroxides, $\text{Ba}{\left(\text{OH}\right)}_{\text{2}}\text{and Sr}{\left(\text{OH}\right)}_{\text{2}}$ are soluble in water.

Answer to Problem 75GQ

The compound which is separated by stirring the solid mixture with water is found as $\text{NaOH}$.

Explanation of Solution

$\text{NaOH}$ can be separated by stirring with water, because, most of the metal hydroxides and oxides are insoluble in water, $\text{NaOH}$ is soluble in water.  Therefore, ${\text{Ca(OH)}}_{\text{2}}$ is insoluble in water.

Interpretation Introduction

Interpretation:

The mixture containing $\text{NaOH}$ and $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$, the compound which is separated by stirring the solid mixture with water should be identified.

Concept introduction:

Most of the ionic compounds are soluble in water, very few of the ionic compounds are sparingly soluble, and some of the ionic compounds are insoluble in water.  When it is soluble in water ions gets separated in the solution.

Soluble compounds in water

Almost all the salts of ${\text{Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, NH}}_{\text{4}}{}^{\text{+}}\text{,}\left({\text{NO}}_{\text{3}}{}^{\text{-}}\right)\text{,}\left({\text{ClO}}_{\text{3}}{}^{\text{-}}\right)\text{,}\left({\text{ClO}}_{\text{4}}{}^{\text{-}}\right)\text{and}\left({\text{CH}}_{\text{3}}{\text{CO}}_{\text{2}}{}^{\text{-}}\right)$ are soluble.

Almost all the salts of ${\text{Cl}}^{\text{-}}{\text{, Br}}^{\text{-}}{\text{, I}}^{\text{-}}\left(\text{halides}\right)$ are soluble. But some of the halides $\left({\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}\right)$ are insoluble.

Salts of F^- are soluble. But some of the fluoride salt of ${\text{Mg}}^{\text{2+}}{\text{, Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble.

Salts of $\text{sulfate }\left({\text{SO}}_{\text{4}}{}^{\text{2-}}\right)$ are soluble.  But sulfates of ${\text{Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}{\text{, Ag}}^{\text{+}}\text{,}$ are insoluble.

Insoluble compounds in water:

Most of the salts of $\left({\text{CO}}_{\text{3}}{}^{\text{2-}}\right)\text{,}\left({\text{PO}}_{\text{4}}{}^{\text{3-}}\right)\text{,}\left({\text{C}}_{\text{2}}{\text{O}}_{\text{4}}{}^{\text{2-}}\right)\text{,}\left({\text{CrO}}_{\text{4}}{}^{\text{2-}}\right)\text{ and}\left({\text{S}}^{\text{2-}}\right)$ are insoluble but some of the salts of NH₄⁺, alkali metal cations and $\text{BaS}$ are soluble.

Most of the metal hydroxides and oxides are insoluble in water bit some of the alkali metal hydroxides, $\text{Ba}{\left(\text{OH}\right)}_{\text{2}}\text{and Sr}{\left(\text{OH}\right)}_{\text{2}}$ are soluble in water.

Answer to Problem 75GQ

The compound which is separated by stirring the solid mixture with water is found as

${\text{MgCl}}_{\text{2}}$.

Explanation of Solution

${\text{MgCl}}_{\text{2}}$ can be separated by stirring with water, because, Salts of F^- are soluble. But some of the fluoride salt of ${\text{Mg}}^{\text{2+}}{\text{, Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble.  Therefore, ${\text{MgF}}_{\text{2}}$ is insoluble in water.

Interpretation Introduction

Interpretation:

The mixture containing $\text{NaOH}$ and $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$, the compound which is separated by stirring the solid mixture with water should be identified.

Concept introduction:

Most of the ionic compounds are soluble in water, very few of the ionic compounds are sparingly soluble, and some of the ionic compounds are insoluble in water.  When it is soluble in water ions gets separated in the solution.

Soluble compounds in water

Almost all the salts of ${\text{Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, NH}}_{\text{4}}{}^{\text{+}}\text{,}\left({\text{NO}}_{\text{3}}{}^{\text{-}}\right)\text{,}\left({\text{ClO}}_{\text{3}}{}^{\text{-}}\right)\text{,}\left({\text{ClO}}_{\text{4}}{}^{\text{-}}\right)\text{and}\left({\text{CH}}_{\text{3}}{\text{CO}}_{\text{2}}{}^{\text{-}}\right)$ are soluble.

Almost all the salts of ${\text{Cl}}^{\text{-}}{\text{, Br}}^{\text{-}}{\text{, I}}^{\text{-}}\left(\text{halides}\right)$ are soluble. But some of the halides $\left({\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}\right)$ are insoluble.

Salts of F^- are soluble. But some of the fluoride salt of ${\text{Mg}}^{\text{2+}}{\text{, Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble.

Salts of $\text{sulfate }\left({\text{SO}}_{\text{4}}{}^{\text{2-}}\right)$ are soluble.  But sulfates of ${\text{Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}{\text{, Ag}}^{\text{+}}\text{,}$ are insoluble.

Insoluble compounds in water:

Most of the salts of $\left({\text{CO}}_{\text{3}}{}^{\text{2-}}\right)\text{,}\left({\text{PO}}_{\text{4}}{}^{\text{3-}}\right)\text{,}\left({\text{C}}_{\text{2}}{\text{O}}_{\text{4}}{}^{\text{2-}}\right)\text{,}\left({\text{CrO}}_{\text{4}}{}^{\text{2-}}\right)\text{ and}\left({\text{S}}^{\text{2-}}\right)$ are insoluble but some of the salts of NH₄⁺, alkali metal cations and $\text{BaS}$ are soluble.

Most of the metal hydroxides and oxides are insoluble in water bit some of the alkali metal hydroxides, $\text{Ba}{\left(\text{OH}\right)}_{\text{2}}\text{and Sr}{\left(\text{OH}\right)}_{\text{2}}$ are soluble in water.

Answer to Problem 75GQ

The compound which is separated by stirring the solid mixture with water is found as

$\text{KI}$.

Explanation of Solution

$\text{KI}$ can be separated by stirring with water, because, almost all the salts of ${\text{Cl}}^{\text{-}}{\text{, Br}}^{\text{-}}{\text{, I}}^{\text{-}}\left(\text{halides}\right)$ are soluble.  But some of the halides are $\left({\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}\right)$ are insoluble. $\text{AgI}$ is insoluble in water.

Interpretation Introduction

Interpretation:

The mixture containing $\text{NaOH}$ and $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$, the compound which is separated by stirring the solid mixture with water should be identified.

Concept introduction:

Most of the ionic compounds are soluble in water, very few of the ionic compounds are sparingly soluble, and some of the ionic compounds are insoluble in water.  When it is soluble in water ions gets separated in the solution.

Soluble compounds in water

Almost all the salts of ${\text{Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, NH}}_{\text{4}}{}^{\text{+}}\text{,}\left({\text{NO}}_{\text{3}}{}^{\text{-}}\right)\text{,}\left({\text{ClO}}_{\text{3}}{}^{\text{-}}\right)\text{,}\left({\text{ClO}}_{\text{4}}{}^{\text{-}}\right)\text{and}\left({\text{CH}}_{\text{3}}{\text{CO}}_{\text{2}}{}^{\text{-}}\right)$ are soluble.

Almost all the salts of ${\text{Cl}}^{\text{-}}{\text{, Br}}^{\text{-}}{\text{, I}}^{\text{-}}\left(\text{halides}\right)$ are soluble. But some of the halides $\left({\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}\right)$ are insoluble.

Salts of F^- are soluble. But some of the fluoride salt of ${\text{Mg}}^{\text{2+}}{\text{, Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble.

Salts of $\text{sulfate }\left({\text{SO}}_{\text{4}}{}^{\text{2-}}\right)$ are soluble.  But sulfates of ${\text{Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}{\text{, Ag}}^{\text{+}}\text{,}$ are insoluble.

Insoluble compounds in water:

Most of the salts of $\left({\text{CO}}_{\text{3}}{}^{\text{2-}}\right)\text{,}\left({\text{PO}}_{\text{4}}{}^{\text{3-}}\right)\text{,}\left({\text{C}}_{\text{2}}{\text{O}}_{\text{4}}{}^{\text{2-}}\right)\text{,}\left({\text{CrO}}_{\text{4}}{}^{\text{2-}}\right)\text{ and}\left({\text{S}}^{\text{2-}}\right)$ are insoluble but some of the salts of NH₄⁺, alkali metal cations and $\text{BaS}$ are soluble.

Most of the metal hydroxides and oxides are insoluble in water bit some of the alkali metal hydroxides, $\text{Ba}{\left(\text{OH}\right)}_{\text{2}}\text{and Sr}{\left(\text{OH}\right)}_{\text{2}}$ are soluble in water.

Answer to Problem 75GQ

The compound which is separated by stirring the solid mixture with water is found as

${\text{NH}}_{\text{4}}\text{Cl}$.

Explanation of Solution

${\text{ NH}}_{\text{4}}\text{Cl}$ can be separated by stirring with water, because, Almost all the salts of ${\text{Cl}}^{\text{-}}{\text{, Br}}^{\text{-}}{\text{, I}}^{\text{-}}\left(\text{halides}\right)$ are soluble.  But some of the halides $\left({\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}\right)$ are insoluble. ${\text{PbCl}}_{\text{2}}$ is insoluble in water.