Identify the gas whose 2gram molecules weighs 64 g

The weight of gas for 2gram molecules = 64g

Then the weight of gas for 1 gram molecules is $\frac{64\mathrm{g}}{2\mathrm{gram} \mathrm{molecules}}\times 1 gram molecules=32g$The gas which has one gram molecule weight as32g is ${\mathrm{O}}_2$ .