Which property of gas is used in supplying oxygen cylinders to hospitals?

The non-$SI$ and $SI$ units of some physical quantities are given in Column $A$ and Column $B$ respectively. Match the units belonging to the same physical quantity:

Column $A$	Column $B$
$(a)$ degree Celsius	$(i)$ kilogram
$(b)$ centimeter	$(ii)$ pascal
$(c)$ gram per centimetre cube	$(iii)$ metre
$(d)$ bar	$(iv)$ kelvin
$(e)$ milligram	$(v)$ kilogram per metre cube

State whether the following statement is true or false:
The force of attraction between the constituent particles in any form of matter is known as intermolecular force.

In which of the following conditions,the distance between the molecules of hydrogen gas would increase?
$(i)$ Increasing pressure on hydrogen contained in a closed container
$(ii)$ Some hydrogen gas leaking out of the container
$(iii)$ Increasing the volume of the container of hydrogen gas
$(iv)$ Adding more hydrogen gas to the container without increasing the volume of the container

Give reasons:
$(a)$ Steam produces more severe burns than boiling water.
$(b)$ We are able to sip hot tea faster from a saucer rather than a cup.
$(c)$ Water kept in an earthen pot becomes cool during summer.

State one difference between a gas and a vapour.