A mixture of ``\ce{N2}`` and Ar gases in a cylinder contains
7 g of ``\ce{N2}`` and 8 g of Ar. If the total pressure of the
mixture of the gases in the cylinder is 27 bar, the
partial pressure of ``\ce{N2}`` is :
[Use atomic masses (in g mol-1) : N=14, Ar=40]
(1) 9 bar
(2) 12 bar
(3) 15 bar
(4) 18 bar