Q14.142CP - Chemistry: Molecular Nature Of Matter And Change

Question

Unlike other Group 2A(2) metals, beryllium reacts like aluminum and zinc with concentrated aqueous base to release hydrogen gas and form oxoanions of formula $\mathbf{M}{\left(\mathbf{OH}\right)}_{\mathbf{4}}{\mathbf{n}}^{-}$ . Write equations for the reactions of these three metals with NaOH.

Step-by-Step Solution

Answer

The formulae for the reactions of these three metals with NaOH

1.  ${\mathrm{Be}}_{\left(\mathrm{s}\right)}+2{\mathrm{NaOH}}_{\left(\mathrm{aq}\right)}+2{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}\stackrel{}{\to }{\mathrm{Na}}_2\mathrm{Be}{(\mathrm{OH}{)}_4}_{\left(\mathrm{aq}\right)}+{{\mathrm{H}}_2}_{\left(\mathrm{g}\right)}$
2.  data-custom-editor="chemistry" $2{\mathrm{Al}}_{\left(\mathrm{s}\right)}+2{\mathrm{NaOH}}_{\left(\mathrm{aq}\right)}+6{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}\stackrel{}{\to }2\mathrm{NaAl}(\mathrm{OH}{)}_{4\left(\mathrm{aq}\right)}+{{\mathrm{H}}_2}_{\left(\mathrm{g}\right)}$
3.  ${\mathrm{Zn}}_{\left(\mathrm{s}\right)}+2{\mathrm{NaOH}}_{\left(\mathrm{aq}\right)}+2{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}\to {\mathrm{Na}}_2\mathrm{Zn}(\mathrm{OH}{)}_{4\left(\mathrm{aq}\right)}+{\mathrm{H}}_{2\left(\mathrm{g}\right)}$

Step 1: The reaction of beryllium with aqueous sodium hydroxide

Hydrogen gas and oxoanions are generated when beryllium combines with aqueous sodium hydroxide.

The following is the equation for this reaction:

${\mathrm{Be}}_{\left(\mathrm{s}\right)}+2{\mathrm{NaOH}}_{\left(\mathrm{aq}\right)}+2{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}\stackrel{}{\to }{\mathrm{Na}}_2\mathrm{Be}{(\mathrm{OH}{)}_4}_{\left(\mathrm{aq}\right)}+{{\mathrm{H}}_2}_{\left(\mathrm{g}\right)}$

Step 2: When aqueous sodium hydroxide interacts with aluminium

Aluminum produces hydrogen gas and oxoanions when it combines with aqueous sodium hydroxide.

The following is the equation for this reaction:

$2{\mathrm{Al}}_{\left(\mathrm{s}\right)}+2{\mathrm{NaOH}}_{\left(\mathrm{aq}\right)}+6{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}\stackrel{}{\to }2\mathrm{NaAl}(\mathrm{OH}{)}_{4\left(\mathrm{aq}\right)}+{{\mathrm{H}}_2}_{\left(\mathrm{g}\right)}$

Step 3: When zinc combines with aqueous sodium hydroxide

Hydrogen gas and oxoanions are generated when zinc combines with aqueous sodium hydroxide.

The following is the equation for this reaction:

${\mathrm{Zn}}_{\left(\mathrm{s}\right)}+2{\mathrm{NaOH}}_{\left(\mathrm{aq}\right)}+2{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}\to {\mathrm{Na}}_2\mathrm{Zn}(\mathrm{OH}{)}_{4\left(\mathrm{aq}\right)}+{\mathrm{H}}_{2\left(\mathrm{g}\right)}$