Types Of Solutions

Step 1: Concept
Benzoic acid in benzene exists as a dimer.
Step 2: Analysis
Association leads to a decrease in the number of solute particles.
Step 3: Conclusion
A lower number of particles results in lower observed osmotic pressure.
Final Answer: (C)

Step 1: Concept
, where is molality.
Step 2: Analysis
* . * . * .
Step 3: Conclusion
.
Final Answer: (D)

Step 1: Concept
Coherence requires a relationship between the phases of waves.
Step 2: Condition
Two sources are coherent if they maintain a constant phase difference over time.
Step 3: Result
This constant difference is necessary for producing a stable interference pattern.
Final Answer: (a)

Step 1: Hadrons
Hadrons include mesons (made of quark-antiquark pairs) and baryons (made of three quarks).
Step 2: Fundamental Units
The basic quark model used to explain all known hadrons relies on combinations of quarks and their corresponding antiquarks.
Step 3: Conclusion
To build the full set of hadrons, the model utilizes 3 quarks and 3 antiquarks.
Final Answer: (c)

Step 1: Using the osmotic pressure formula.
Osmotic pressure ( ) is given by the formula: where is the number of moles of solute, is the gas constant, is the temperature in Kelvin, and is the volume of the solution.

Step 2: Calculation at 150°C.
Converting the temperature to Kelvin: We then calculate the osmotic pressure using the given concentration (5 percent solution), the gas constant, and other known values.

Step 3: Conclusion.
The correct osmotic pressure is .

Step 1: Understanding mole fraction.
The mole fraction of a component in a solution is given by: where is the number of moles of the components.

Step 2: Calculation of moles.
The molar mass of H O is 34 g/mol, and the molar mass of H O is 18 g/mol. For a 20 percent solution of H O , calculate the mass of each component, convert to moles, and then calculate the mole fraction of water.

Step 3: Conclusion.
The mole fraction of water is .

Step 1: Formula / Definition}

Step 2: Calculation / Simplification}


For , (dissociates into )


Step 3: Final Answer

Step 1: Formula / Definition}

Step 2: Calculation / Simplification}

Molality


Step 3: Final Answer

Concept: Association reduces number of particles.

Step 1: Initial particles = 1.

Step 2: Fraction associated = , so remaining = .

Step 3: Associated particles = (since combine into 1).

Step 4: Total particles: Conclusion:
van’t Hoff factor =

Concept:

Step 1: For sucrose, (non-electrolyte).

Step 2: For NaCl, (Na + Cl ).

Step 3: Osmotic pressure .

Step 4: Therefore, Conclusion:
Osmotic pressure = 0.50 atm

Concept: Positive deviation from Raoult’s law occurs when:

Step 1: Understand deviation.
Weaker solute-solvent forces molecules escape easily higher vapor pressure.

Step 2: Conclusion.
Thus, intermolecular forces between solute-solvent are weaker.

Concept: Isotonic solutions have same osmotic pressure:

Step 1: Density = solution = Urea solution:

Step 2: Unknown substance solution: Let molar mass =

Step 3: For isotonic solutions:

Concept: Elevation in boiling point is a colligative property, which depends only on the number of solute particles, not their nature. When a non-volatile solute (like sucrose) is added to a solvent (water), it lowers the vapour pressure. Hence, a higher temperature is required for the solution to boil. where:
• = elevation in boiling point
• = molal elevation constant
• = molality

Step 1: Required elevation in boiling point:

Step 2: Calculate molality:

Step 3: Mass of solvent:

Step 4: Molar mass of sucrose:

Step 5: Mass required: Final: