At 35   o C , the vapour pressure of C S 2 , is 512 m m Hg and that of acetone is 144   m m H g .…

At 35 oC, the vapour pressure of CS2, is 512mm Hg and that of acetone is 144 mmHg. A solution of CS2 in acetone has a total vapour pressure of 600 mmHg . The false statement amongst the following is:
  1. Raoult's law is not obeyed by this system
  2. a mixture of 100mLCS2 and 100mL acetone has a volume <200mL
  3. CS2 and acetone are less attracted to each other than to themselves
  4. heat must be absorbed in order to produce the solution at 35oC

Solution

P observed =600
 
P Cal = P A 0 x A +P B 0 x B

=512x+344−344x

=168x+344

=512 (If x=1 for maximum value)

Thus,   P cal < P observed

Thus' the process is deviated from Raoult's law, showing positive deviation from Raoult's law.

ΔH>0 , i.e., is absorbed

Asked in: JEE Main 2020 (07 Jan Shift 1)

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