General
✓✗The two metals which can be extracted just by heating their sulphides in air are
- sodium and copper
- copper and aluminium
- potassium and zinc
- mercury and copper
General
✓✗During the refining of an impure metal by electrolysis, the pure metal gets deposited
- at cathode
- on the walls of electrolytic tank
- at anode
- at the bottom of electrolytic tank
General
✓✗The articles made of silver metal become dark on prolonged exposure to air. This is due to the formation of a layer of its:
- Oxide
- Hydride
- Sulphide
- Carbonate
General
✓✗In roasting, ore is heated in
- absence of air
- presence of pure oxygen
- presence of sufficient air
- limited supply of air
General
✓✗Melting point of Gallium is
- 10°C
- 30°C
- 80°C
- 97°C
General
✓✗Aluminium metals starts to look dull over a period of time due to formation of a layer of
- Aluminium carbonate
- Aluminium hydroxide
- Aluminium oxide
- Aluminium sulphide
General
✓✗For the formation of a triple bond how many electrons are to be shared ?
- 3
- 3 pairs
- 4 pairs
- 6 pairs
General
✓✗Sodium, potassium and calcium can react with
- cold water
- hot water only
- steam only
- they are non reactive
General
✓✗Roasting is generally done in the case of
- oxide ores
- silicate ores
- sulphide ores
- carbonate ores
General
✓✗Which pair of the following metals does not react with sulphuric acid?
- Cu and Ag
- Au and Pt
- Pb and Au
- Mg and Pt