Write an equation for the reaction of:

Here are the solutions to the questions:

4. (d) Write an equation for the reaction of:

• (i) Carbon dioxide with aqueous potassium hydroxide.

  $$\boxed{\text{CO}_2(g) + 2\text{KOH}(aq) \to \text{K}_2\text{CO}_3(aq) + \text{H}_2\text{O}(l)}$$

• (ii) Germanium monoxide with dilute hydrochloric acid.

  $$\boxed{\text{GeO}(s) + 2\text{HCl}(aq) \to \text{GeCl}_2(aq) + \text{H}_2\text{O}(l)}$$

4. (e)

• (i) Give the formula of the stable oxides of the elements of Period 3 in the table below.

  Symbol of element	Na	Mg	Al	Si	P	S	Cl	Ar
  Formula of oxide	$\boxed{\text{Na}_2\text{O}}$	$\boxed{\text{MgO}}$	$\boxed{\text{Al}_2\text{O}_3}$	$\boxed{\text{SiO}_2}$	$\boxed{\text{P}_4\text{O}_{10}}$	$\boxed{\text{SO}_3}$	$\boxed{\text{Cl}_2\text{O}_7}$	$\boxed{\text{None}}$

• (ii) From the table above, select an amphoteric oxide and write balanced equations to show its reactions with hydrochloric acid and sodium hydroxide.

  • Amphoteric oxide: $\boxed{\text{Al}_2\text{O}_3}$

  • Reaction with $\text{HCl}(aq)$:

    $$\boxed{\text{Al}_2\text{O}_3(s) + 6\text{HCl}(aq) \to 2\text{AlCl}_3(aq) + 3\text{H}_2\text{O}(l)}$$

  • Reaction with $\text{NaOH}(aq)$:

    $$\boxed{\text{Al}_2\text{O}_3(s) + 2\text{NaOH}(aq) + 3\text{H}_2\text{O}(l) \to 2\text{Na}[\text{Al}(\text{OH})_4](aq)}$$