Which gas can be adsorbed on a metal and released when required?

Name one metal and one non-metal that exist in liquid state at room temperature. Also,name two metals having a melting point less than $310\ K$ $(37\ ^\circ C)$.

Which of the following properties is generally not shown by metals?

Which type of oxide is $CO_{2}$?

Which of the following fuels has the highest calorific value?

In a blast furnace,what prevents the oxidation of molten iron?