Question

A solution contains 0.32 mol naphthalene in 5.50 mol of toluene at 32°C. Pure toluene has a vapor pressure of 41 torr at this temperature. Which of the following options correctly solve for both P and AP for this solution? Select all that apply. Check all that apply. 5.50 PE x 41 = 39 torr 0.32+5.50 AP0.32 2 x 41=2.4 torr 5.50 P 0.32 -X41 2.3 tort 0.32 +5.50 BP 0.32-35.60 41–23.00 32 +5.50

Answer 1

According to Raoult's law for a solution of volatile liquids, the partial pressure of a solvent is directly proportional to the mole fraction of that solvent.

Let us assume two volatile liquids A & B

P_{​​​​​​A} = X_{​​​​​​A} P°_{​​​​​​A}

P_{​​​​​​B}= X_​​B P°_{​​​​​​B}

Given that

Number of moles of Toluene = 5.50 moles

Number of moles of Naphthalene = 0.32 moles

Mole fraction of Naphthalene = 0.32/0.32+5.50

Mole fraction of Toluene = 5.50/0.32+5.50

Pressure of pure Toluene = 41 torr

Partial pressure of toluene =( 0.32 /(0.32+5.5) ) * 41 torr

= 2.3 torr