# The density of a gas at STP is 2.68g/L . The gas may be

$(a)\;NO_2\qquad(b)\;Kr\qquad(c)\;COS\qquad(d)\;SO_2$

d = $\large\frac{PM}{RT}$
$\therefore M = \large\frac{dRT}{p}$
$=\large\frac{2.68\times0.0821\times273}{1}$
=60.1
i.e COS(12+16+32) = 60