Answer:
(a) The processes involved in:
(i) Dressing of ores are:
- Hydraulic washing
- Magnetic separation
- Froth floatation
- Chemical method/Leaching
(ii) Refining of ores are:
- Distillation
- Liquation
- Electrorefining
(b) The two metallic oxides that cannot be reduced by carbon, carbon monoxide or hydrogen are oxides of sodium and potassium.