7.5 grams of a gas occupy 5.8 liters of volume at STP the gas is closer to

5.8 L of gas has mass = 7.5 g

$\therefore 22.4\mathrm{L}\text{ of gas has mass }=\frac{7.5}{5.8}\times 22.4=28.96$

So molecular weight = 29

So, molecular formula of compound is NO.