Chapter 3, Problem 77GQ

(a)

Interpretation Introduction

Interpretation:

The compound (s) that conduct only very weak electricity when dissolved in water should be identified.

Concept introduction:

Acids can donate the ${\text{H}}^{\text{+}}$ ion, base can accept the ${\text{H}}^{\text{+}}$ ion or donate the ${\text{OH}}^{\text{-}}$ ion,

strong acids or strong bases are ionize in water very easily, weak acid or weak bases are ionize very slowly.

strong acid and sarong base are one that completely ionizes (dissociates) in a solution (provided there is sufficient solvent).  In water, acid HA dissolves and gives ${\text{H}}^{\text{+}}$ (as hydronium ion ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ ion).  Bases dissolve and gives ${\text{OH}}^{\text{-}}$ ion.

Conductor of electricity depends on the movements of the ions in solution, ions gets separated, it behaves as strong conductor of electricity.  If the ions not completely dissociate that will be a very weak conductor of electricity

Strong electricity conductors are strong acids and weak bases.

Weak electricity conductors are weak acid and weak bases.

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 are $\left({\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}\right)$ 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 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.

Water soluble compounds are ionize in water and conduct the electricity, strongly conduct the electricity compounds are completely soluble in water.  Slightly soluble compounds are weak conductor of electricity.

(b)

Interpretation Introduction

Interpretation:

The compound (s) that conduct only very weak electricity when dissolved in water should be identified.

Concept introduction:

Acids can donate the ${\text{H}}^{\text{+}}$ ion, base can accept the ${\text{H}}^{\text{+}}$ ion or donate the ${\text{OH}}^{\text{-}}$ ion,

strong acids or strong bases are ionize in water very easily, weak acid or weak bases are ionize very slowly.

strong acid and sarong base are one that completely ionizes (dissociates) in a solution (provided there is sufficient solvent).  In water, acid HA dissolves and gives ${\text{H}}^{\text{+}}$ (as hydronium ion ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ ion).  Bases dissolve and gives ${\text{OH}}^{\text{-}}$ ion.

Conductor of electricity depends on the movements of the ions in solution, ions gets separated, it behaves as strong conductor of electricity.  If the ions not completely dissociate that will be a very weak conductor of electricity

Strong electricity conductors are strong acids and weak bases.

Weak electricity conductors are weak acid and weak bases.

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 are $\left({\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}\right)$ 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 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.

Water soluble compounds are ionize in water and conduct the electricity, strongly conduct the electricity compounds are completely soluble in water.  Slightly soluble compounds are weak conductor of electricity.