UGC NET Exam  >  UGC NET Questions  >  A solution is formed of 45 g Napthelene (a no... Start Learning for Free
A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C
(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)
  • a)
    96 torr
  • b)
    90 torr
  • c)
    68.86 torr
  • d)
    27.168 torr
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
A solution is formed of 45 g Napthelene (a non-volatile compound, MW =...
The vapor pressure of this kind of solvent is related to the mole fraction of the solvent and its pure vapor pressure:
vapor pressure of the solution = mole fraction of solvent times vapor pressure of the pure solvent
This is known as Raoult's Law.
moles naphthalene → 45 g / 128 g/mol = 0.351 mol
moles ethanol → 40.65 g / 46.02 g/mol = 0.891 mol
mole fraction ethanol → 0.891 / (0.891 + 0.351) = 0.717
vapor pressure of solution → 96 torr × 0.717 = 68.86 torr
View all questions of this test
Most Upvoted Answer
A solution is formed of 45 g Napthelene (a non-volatile compound, MW =...
Calculation of Vapor Pressure of Solution:

Step 1: Calculate the mole fraction of each component in the solution.
Given:
Mass of Napthelene (C10H8) = 45 g
Molar mass of Napthelene (C10H8) = 128 g/mol
Mass of ethanol (C2H5OH) = 41 g
Molar mass of ethanol (C2H5OH) = 46.02 g/mol
Moles of Napthelene = 45 g / 128 g/mol = 0.3516 mol
Moles of ethanol = 41 g / 46.02 g/mol = 0.8918 mol
Total moles of solution = 0.3516 + 0.8918 = 1.2434 mol
Mole fraction of Napthelene = 0.3516 / 1.2434 = 0.2831
Mole fraction of ethanol = 0.8918 / 1.2434 = 0.7169

Step 2: Calculate the partial pressure of each component.
Vapor pressure of pure ethanol = 96 torr
Partial pressure of ethanol = mole fraction of ethanol * vapor pressure of pure ethanol
Partial pressure of ethanol = 0.7169 * 96 torr = 68.86 torr

Step 3: Calculate the total vapor pressure of the solution.
Total vapor pressure = partial pressure of Napthelene + partial pressure of ethanol
Total vapor pressure = 0 + 68.86 torr = 68.86 torr
Therefore, the vapor pressure of the solution at 25 °C is 68.86 torr.
Explore Courses for UGC NET exam
A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer?
Question Description
A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer? for UGC NET 2025 is part of UGC NET preparation. The Question and answers have been prepared according to the UGC NET exam syllabus. Information about A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for UGC NET 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer?.
Solutions for A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for UGC NET. Download more important topics, notes, lectures and mock test series for UGC NET Exam by signing up for free.
Here you can find the meaning of A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer?, a detailed solution for A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer? has been provided alongside types of A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice A solution is formed of 45 g Napthelene (a non-volatile compound, MW = 128 g/mol) and 41 g of ethanol (MW = 46.02 g/mol). Find the vapor pressure of solution at 25 °C(The vapor pressure of pure ethanol at 25.0 °C is 96 torr)a)96 torrb)90 torrc)68.86 torrd)27.168 torrCorrect answer is option 'C'. Can you explain this answer? tests, examples and also practice UGC NET tests.
Explore Courses for UGC NET exam

Top Courses for UGC NET

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev