Answer:
[tex]\implies \sf D = \dfrac{PM}{RT}[/tex]
[tex]\implies \sf 3.35= \dfrac{1 \times M}{ \frac{1}{12} \times 298}[/tex]
[tex]\implies \sf 3.35= \dfrac{12\times M}{ 298}[/tex]
[tex]\implies \sf 3.35 \times 298= 12\times M[/tex]
[tex]\implies \sf 998.3= 12\times M[/tex]
[tex]\implies \sf M = \dfrac{998.3}{12} [/tex]
[tex]\implies \bf M = 83.1917 \: \frac{g}{mol} [/tex]
