Question

This graph shows how the vapor pressure of three liquids varies with temperature: 900 vapor pressure, torr - cyclohexanol - benzaldehyde - dimethyl sulfoxide temperature, °C Use the graph to answer the following questions: most volatile: choose one - Which liquid is the most volatile? Which is the least volatile? least volatile: choose one cyclohexanol: 1 °C What is the normal boiling point of each liquid? Note: your answer must be within 1°C of the exact answer to be graded correct. benzaldehyde: dimethyl sulfoxide: 0°C 1 °C more Suppose a beaker of benzaldehyde is put inside a sealed tank containing benzaldehyde gas at 171. degree C and 608. torr. After ten minutes, will there be more liquid in the beaker, less liquid, or the same amount? less the same

Answer 1

a) According to given data, cyclohexanol is the most volatile, as its vapour pressure increases the most rapidly with increase in temperature.

Dimethyl sulfoxide is the least volatile as its vapour pressure increases the least rapidly with increase in temperature.

b) The boiling point of a substance is when the vapuor pressure becomes equal to the normal atmospheric pressure, which is 760 torr.

Therefore, cyclohexanol is 161 ^oC

Benzaldehyde is 179 ^oC

Dimethyl Sulfoxide is 188 ^oC

c) The same amount of benzaldehyde because the vapour pressure exerted by benzaldehyde in the beaker will be the same as the vapour pressure of the gas, so no further vapourisation or condensation takes place.