A benzene (C₆H₆) solution contains an unknown amount of p-dibromobenzene (C₆H₄Br₂) as a solute. Dry nitrogen is bubbled through the solution at 26.0°C, where it equilibrates with the benzene vapor above the solution. The nitrogen-benzene gaseous mixture is then passed into a cooling trap (to condense the benzene into a liquid) at a temperature where nitrogen is gaseous and the vapor pressure of benzene is negligible. From 100.0 L of the gaseous mixture of nitrogen and benzene, 36.9 g of liquid benzene is collected in the cooling trap. The vapor pressure of pure benzene at 26.0°C is 100 torr. What was the mass percent of p-dibromobenzene in the original solution? (The vapor pressure of p-dibromobenzene is negligible at 26.0°C.)

A benzene (C₆H₆) solution contains an unknown amount of p-dibromobenzene (C₆H₄Br₂) as a solute. Dry nitrogen is bubbled through the solution at 26.0°C, where it equilibrates with the benzene vapor above the solution. The nitrogen-benzene gaseous mixture is then passed into a cooling trap (to condense the benzene into a liquid) at a temperature where nitrogen is gaseous and the vapor pressure of benzene is negligible. From 100.0 L of the gaseous mixture of nitrogen and benzene, 37.2 g of liquid benzene is collected in the cooling trap. What is the vapor pressure (in torr) of the original benzene solution at 26.0°C? (The vapor pressure of p-dibromobenzene is negligible at 26.0°C.)