Which of the following methods is suitable for preventing an iron frying pan from rusting?
Applying grease
Applying paint
Applying a coating of zinc
All the above
The non-metal which conducts electricity,
Sulphur
Graphite
Iodine
Silicon
Silver articles become black on prolonged exposure to air. This is due to the formation of
AgCN
Ag2O
Ag2S
Ag2S and AgCN
Which of the following is not true of metals?
Metals are good conductors of electricity
Metals are malleable and ductile.
Metals form non-polar covalent compounds
Metal will have 1 or 2 or 3 electrons in their valence shell
A non-metal kept under water is
phosphorus
sulphur
Sodium
Potassium
Which is used in machine parts due to its high tensile strength?
Pig iron
Steel
Wrought iron
Hematite
The metal which does not react with dilute H2SO4
Mg
Zn
Al
Hg
The substance added to lower the fusion temperature from 2050oC to 950oC is
alumina
cryolite
Corundum
carborundum
Brass is an alloy of
Copper and tin
Copper and zinc
Zinc and lead
Lead and tin
Food cans are coated with tin and not with zinc because
Zinc is costlier than tin
Zinc has higher melting point than tin
Zinc is more reactive than tin
Zinc is less reactive than tin
