Chapter 3, Problem 29QRT

(a)

Interpretation Introduction

Interpretation:

The solubility of the given Potassium monohydrogen phosphate in water has to be identified. The ions present in the aqueous solution of potassium monohydrogen phosphate has to 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:

All ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$ group and ${\text{NH}}_4^{+}$ compound are soluble, all nitrates $\left({\text{NO}}_{\text{3}}{}^{\text{-}}\right)$ 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 namely ${\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble.

Most of the sulfates are soluble except ${\text{CaSO}}_{\text{4}}{\text{, SrSO}}_{\text{4}}{\text{, BaSO}}_{\text{4}}{\text{ and PbSO}}_{\text{4}}$ are insoluble.

All the chlorate $\left({\text{ClO}}_{\text{3}}{}^{\text{-}}\right)$, perchlorate $\left({\text{ClO}}_{\text{4}}{}^{\text{-}}\right)$, acetate $\left({\text{CH}}_{\text{3}}{\text{CO}}_{\text{2}}{}^{\text{-}}\right)$ are soluble.

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 ${\text{Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}{\text{, Ag}}^{\text{+}}$ are insoluble.

Insoluble compounds in water:

All phosphates $\left({\text{PO}}_{\text{4}}{}^{\text{3-}}\right)$ and carbonates $\left({\text{CO}}_{\text{3}}{}^{\text{2-}}\right)$ are insoluble except ${\text{NH}}_4^{+}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$.

All chromates $\left({\text{CrO}}_{\text{4}}{}^{\text{2-}}\right)$ are insoluble except ${\text{NH}}_4^{+}$, ${\text{Mg}}^{\text{2+}}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$.

All hydroxides are insoluble except ${\text{NH}}_4^{+}$, ${\text{Mg}}^{\text{2+}}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$. $\text{Sr}{\left(\text{OH}\right)}_{\text{2}}\text{, Ba}{\left(\text{OH}\right)}_{\text{2}}\text{, and Ca}{\left(\text{OH}\right)}_{\text{2}}$ are slightly soluble.

All oxalates $\left({\text{C}}_{\text{2}}{\text{O}}_{\text{4}}{}^{\text{2-}}\right)$ are insoluble except ${\text{NH}}_4^{+}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$.

All sulfides $\left({\text{S}}^{\text{2-}}\right)$ are insoluble except ${\text{NH}}_4^{+}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$ and Group 2A ($\text{MgS, CaS, and BaS}$ are sparingly 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.

Dissociation:

When ionic compound dissolved in water it produced cation and anion, this process is called as dissociation.

Generally the ionic compound consists of cation and anion.

Cation: When electrons are removed from the atom that results to form positively charged ion called cation.

Anion: Addition of electron to atom results to form negatively charged ion called anion.

Explanation of Solution

The given compound is shown below,

   Potassium monohydrogen phosphate (${\text{K}}_{\text{2}}{\text{HPO}}_{\text{4}}$)

All ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$ group and ${\text{NH}}_4^{+}$ compound are soluble, therefore Potassium monohydrogen phosphate (${\text{K}}_{\text{2}}{\text{HPO}}_{\text{4}}$) is soluble in water.

The dissociation of potassium monohydrogen phosphate (${\text{K}}_{\text{2}}{\text{HPO}}_{\text{4}}$) is given below,

  ${\text{K}}_{\text{2}}{\text{HPO}}_{\text{4}}\to {\text{ 2K}}^{\text{+}}{\text{(aq) + HPO}}_4^{2-}\text{(aq)}$

Therefore, $\text{KOH}$ is dissolved in water (dissociation) gives ${\text{K}}^{\text{+}}\text{(aq)}$ and ${\text{HPO}}_4^{2-}$.

(b)

Interpretation Introduction

Interpretation:

  The solubility of the given Sodium hypochlorite in water has to be identified. The ions present in the aqueous solution of Sodium hypochlorite has to be identified.

Concept introduction:

Refer to part (a)

Explanation of Solution

The given compound is shown below,

   Sodium hypochlorite

All ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$ group and ${\text{NH}}_4^{+}$ compound are soluble, therefore Sodium hypochlorite ($\text{NaOCl}$) is soluble in water.

The dissociation of Sodium hypochlorite ($\text{NaOCl}$) is given below,

  $\text{NaOCl }\to {\text{ Na}}^{\text{+}}{\text{(aq) + OCl}}^{\text{-}}\text{(aq)}$

Therefore, Sodium hypochlorite ($\text{NaOCl}$) is dissolved in water (dissociation) gives ${\text{ Na}}^{\text{+}}\text{(aq) }$ and ${\text{OCl}}^{\text{-}}\text{(aq)}$.

(c)

Interpretation Introduction

Interpretation:

  The solubility of the given Magnesium chloride in water has to be identified. The ions present in the aqueous solution of Magnesium chloride has to be identified.

Concept introduction:

Refer to part (a)

Explanation of Solution

The given compound is shown below,

  Magnesium chloride

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 namely ${\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble, therefore Magnesium chloride (${\text{MgCl}}_{\text{2}}$) is soluble in water.

The dissociation of Magnesium chloride (${\text{MgCl}}_{\text{2}}$) is given below,

  ${\text{MgCl}}_{\text{2}}\to {\text{ Mg}}^{\text{2+}}{\text{(aq) + 2Cl}}^{\text{-}}\text{(aq)}$

Therefore, Magnesium chloride (${\text{MgCl}}_{\text{2}}$) is dissolved in water (dissociation) gives ${\text{Mg}}^{\text{2+}}\text{(aq)}$ and ${\text{Cl}}^{\text{-}}\text{(aq)}$.

(d)

Interpretation Introduction

Interpretation:

The solubility of the given Calcium hydroxide in water has to be identified. The ions present in the aqueous solution of Calcium hydroxide has to be identified.

Concept introduction:

Refer to part (a)

Explanation of Solution

The given compound is shown below,

   Calcium hydroxide.

All hydroxides are insoluble except ${\text{NH}}_4^{+}$, ${\text{Mg}}^{\text{2+}}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$. $\text{Sr}{\left(\text{OH}\right)}_{\text{2}}\text{, Ba}{\left(\text{OH}\right)}_{\text{2}}\text{, and Ca}{\left(\text{OH}\right)}_{\text{2}}$ are slightly soluble, therefore Calcium hydroxide ($\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$) is soluble in water.

The dissociation of Calcium hydroxide ($\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$) is given below,

  $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}\to {\text{ Ca}}^{\text{2+}}{\text{(aq) + 2OH}}^{\text{-}}\text{(aq)}$

Therefore, Calcium hydroxide ($\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$) is dissolved in water (dissociation) gives ${\text{Ca}}^{\text{2+}}\text{(aq)}$ and ${\text{OH}}^{\text{-}}\text{(aq)}$.

(e)

Interpretation Introduction

Interpretation:

The solubility of the given Aluminum bromide in water has to be identified. The ions present in the aqueous solution of Aluminum bromide has to be identified.

Concept introduction:

Refer to part (a)

Explanation of Solution

The given compound is shown below,

  Aluminum bromide

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 namely ${\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble, therefore Aluminum bromide (${\text{AlBr}}_{\text{3}}$) is soluble in water.

The dissociation of Aluminum bromide (${\text{AlBr}}_{\text{3}}$) is given below,

  ${\text{AlBr}}_{\text{3}}\to {\text{ Al}}^{\text{3+}}{\text{(aq) + 3Br}}^{\text{-}}\text{(aq)}$

Therefore, Aluminum bromide (${\text{AlBr}}_{\text{3}}$) is dissolved in water (dissociation) gives ${\text{Al}}^{\text{3+}}\text{(aq)}$ and ${\text{Br}}^{\text{-}}\text{(aq)}$.