Question

properties of metalic oxides

Answer 1

Answer on Question #44799–Chemistry–Inorganic Chemistry

Question

Properties of metallic oxides.

Answer

1) Physical properties of metal oxides

Metal oxides are crystalline solids with high melting point (> 1000°C). Metal oxides are insulators, i.e. they do not conduct electricity.

2) Chemical properties of metal oxides

All metal oxides react with acids resulting in salt and water formation, e.g.

$$\begin{array}{l} \mathrm{Al_2O_3} + 6 \mathrm{HCl} \rightarrow 2 \mathrm{AlCl_3} + 3 \mathrm{H_2O} \\ \mathrm{Na_2O} + \mathrm{H_2SO_4} \rightarrow \mathrm{Na_2SO_4} + \mathrm{H_2O} \end{array}$$

Metal oxides can react with nonmetal oxides (under heating) resulting in salts formation, e.g.

$$\begin{array}{l} 3 \mathrm{K_2O} + \mathrm{P_2O_5} \rightarrow 2 \mathrm{K_3PO_4} \\ \mathrm{ZnO} + \mathrm{SO_3} \rightarrow \mathrm{ZnSO_4} \end{array}$$

Oxides of all alkaline metals and such alkaline-earth metals as Ca, Sr, Ba and Ra react with water resulting in corresponding bases formation, e.g.

$$\begin{array}{l} 2 \mathrm{LiO} + \mathrm{H_2O} \rightarrow 2 \mathrm{LiOH} \\ \mathrm{CaO} + \mathrm{H_2O} \rightarrow \mathrm{Ca(OH)_2} \end{array}$$

Amphoteric oxides, namely such oxides as BeO, ZnO, Al₂O₃, Cr₂O₃, Fe₂O₃ etc. can react with alkalies resulting in salts and water formation and with oxides of alkaline metals resulting in salts formation, e.g.

$$\begin{array}{l} \mathrm{BeO} + \mathrm{NaOH} \rightarrow \mathrm{Na_2BeO_2} + \mathrm{H_2O} \\ \mathrm{Cr_2O_3} + \mathrm{K_2O} \rightarrow 2 \mathrm{KCrO_2} \end{array}$$

Metal oxides can participate in red-ox reaction acting as an oxidant. Such reactions are carried out at high temperatures using coke or such metals as Al or Mg as reducing agents, e.g.

$$\begin{array}{l} 2 \mathrm{Fe_2O_3} + 3 \mathrm{C} \rightarrow 4 \mathrm{Fe} + 3 \mathrm{CO_2} \\ \mathrm{Cr_2O_3} + 2 \mathrm{Al} \rightarrow 2 \mathrm{Cr} + \mathrm{Al_2O_3} \end{array}$$

www.AssignmentExpert.com