Chapter 8, Problem 8E.4E

(a)

Interpretation Introduction

Interpretation:

The balanced chemical equation for the reaction between aluminium oxide and hydroxide ion has to be written.

Answer to Problem 8E.4E

The balanced chemical equation for the reaction between aluminium oxide and hydroxide ion is,

  ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3(s)}}{\text{+2OH}}^{\text{-}}{}_{\left(\text{aq}\right)}{\text{+3H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }\text{2Al}{\left(\text{OH}\right)}_{\text{4}}{{}^{\text{-}}}_{\left(\text{aq}\right)}$

Explanation of Solution

Aluminium oxide reacts with hydroxide ion and water to form $\text{Al}{\left(\text{OH}\right)}_{\text{4}}{}^{\text{-}}.$  The chemical reaction is,

  ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3(s)}}{\text{+OH}}^{\text{-}}{}_{\left(\text{aq}\right)}{\text{+H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }\text{Al}{\left(\text{OH}\right)}_{\text{4}}{{}^{\text{-}}}_{\left(\text{aq}\right)}$

Two moles of hydroxide ion, three moles of water are required in the reactant side and two mole of $\text{Al}{\left(\text{OH}\right)}_{\text{4}}{}^{\text{-}}$ are required in the product side to make the reaction a balanced one.  The balanced chemical equation for the reaction between aluminium oxide and hydroxide ion is,

  ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3(s)}}{\text{+2OH}}^{\text{-}}{}_{\left(\text{aq}\right)}{\text{+3H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }\text{2Al}{\left(\text{OH}\right)}_{\text{4}}{{}^{\text{-}}}_{\left(\text{aq}\right)}$

(b)

Interpretation Introduction

Interpretation:

The balanced chemical equation for the reaction between aluminium, hydronium ion and water has to be written.

Answer to Problem 8E.4E

The balanced chemical equation for the reaction between aluminium, hydronium ion and water is,

  ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3(s)}}{\text{+6H}}_{\text{3}}{\text{O}}^{\text{+}}{}_{\left(\text{aq}\right)}{\text{+3H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }\text{2Al}{\left({\text{H}}_{\text{2}}\text{O}\right)}_{\text{6}}{{}^{\text{3+}}}_{\left(\text{aq}\right)}$

Explanation of Solution

Aluminium reacts with hydronium ion and water to form $\text{Al}{\left({\text{H}}_{\text{2}}\text{O}\right)}_{\text{6}}{}^{\text{3+}}\text{.}$  The chemical reaction is,

  ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3(s)}}{\text{+H}}_{\text{3}}{\text{O}}^{\text{+}}{}_{\left(\text{aq}\right)}{\text{+H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }\text{Al}{\left({\text{H}}_{\text{2}}\text{O}\right)}_{\text{6}}{{}^{\text{3+}}}_{\left(\text{aq}\right)}$

Six moles of hydronium ion, three moles of water are required in the reactant side and two moles of $\text{Al}{\left({\text{H}}_{\text{2}}\text{O}\right)}_{\text{6}}{}^{\text{3+}}$ are required in the product side to make the reaction a balanced one.  The balanced chemical equation for the reaction between aluminium, hydronium ion and water is,

  ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3(s)}}{\text{+6H}}_{\text{3}}{\text{O}}^{\text{+}}{}_{\left(\text{aq}\right)}{\text{+3H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }\text{2Al}{\left({\text{H}}_{\text{2}}\text{O}\right)}_{\text{6}}{{}^{\text{3+}}}_{\left(\text{aq}\right)}$

(c)

Interpretation Introduction

Interpretation:

The balanced chemical equation for the reaction between boron and ammonia has to be written.

Answer to Problem 8E.4E

The balanced chemical equation for the reaction between boron and ammonia is,

  ${\text{2B}}_{\left(\text{s}\right)}{\text{+2NH}}_{\text{3(g)}}\stackrel{}{\to }{\text{2BN}}_{\left(\text{s}\right)}{\text{+3H}}_{\text{2(g)}}$

Explanation of Solution

Boron reacts with ammonia to form boron nitride with the evolution of hydrogen gas.  The chemical reaction is,

  ${\text{B}}_{\left(\text{s}\right)}{\text{+NH}}_{\text{3(g)}}\stackrel{}{\to }{\text{BN}}_{\left(\text{s}\right)}{\text{+H}}_{\text{2(g)}}$

Two moles of boron, two moles of ammonia are required in the reactant side and two moles of boron nitride and three moles of hydrogen are required in the product side to make the reaction a balanced one.  The balanced chemical equation for the reaction between boron and ammonia is,

  ${\text{2B}}_{\left(\text{s}\right)}{\text{+2NH}}_{\text{3(g)}}\stackrel{}{\to }{\text{2BN}}_{\left(\text{s}\right)}{\text{+3H}}_{\text{2(g)}}$