Which method is used to collect $H_2$ gas in a gas jar in the laboratory?

List three properties of sodium in which it differs from the general physical properties of most metals.

Which metal oxide cannot be reduced by carbon?

Which one of the following properties is not generally exhibited by ionic compounds?

Which of the following is a mineral of sulfur?

Give reasons for the following:
$(i)$ Alloys are used in electrical heating devices rather than pure metals.
$(ii)$ Gold ornaments look new even after several years of use.
$(iii)$ An iron grill should be painted frequently.