<p>510 mg of a liquid on vaporiation in Victor Meyer&#39;s apparatus displaces 67.2&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>c</mi><msup><mi>m</mi><mn>3</mn></msup></math>&nbsp;of air at&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced><mrow><mi>S</mi><mi>T</mi><mi>P</mi></mrow></mfenced></math>. The molar mass of the liquid is:</p>