NEET Chemistry: Concentration methods and Raoult's Law Practice Questions
11 free multiple-choice questions on Concentration methods and Raoult's Law (Solutions) for NEET Chemistry, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. In an ideal solution, the partial vapor pressure of component A above the solution is directly proportional to which quantity?
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Correct answer: C — Mole fraction of A
According to Raoult's Law for ideal solutions, the partial vapor pressure of a component is proportional to its mole fraction in the liquid phase (P_A = X_A P_Aᵒ).
Q2. Which concentration unit is based on the mass of the solvent and is typically used when dealing with colligative properties?
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Correct answer: C — Molality
Molality (moles of solute per kg of solvent) is the standard unit used for colligative properties because it depends on the amount of solute particles, not mass, which is temperature independent.
Q3. If a solution is prepared by mixing two liquids, A and B, Raoult's law implies that the partial vapor pressure of A is given by:
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Correct answer: A — P_A = X_A P_Aᵒ
Raoult's Law states that the partial vapor pressure of a component is equal to the mole fraction of that component multiplied by its vapor pressure over the pure liquid (P_A = X_A P_Aᵒ).
Q4. Which of the following is the correct unit for expressing the mole fraction of a component in a solution?
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Correct answer: B — Mole fraction
Mole fraction is defined as the ratio of the moles of a specific component to the total moles of all components in the solution.
Q5. Which colligative property is directly proportional to the concentration of solute particles in a solution?
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Correct answer: B — Osmotic Pressure
Colligative properties (like vapor pressure lowering and osmotic pressure) depend solely on the number of solute particles present in a given amount of solvent, which is directly related to concentration.
Q6. If the vapor pressure of a liquid mixture is lower than expected based on Raoult's law calculations, the solution is typically considered to be:
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Correct answer: A — Non-ideal (Positive deviation)
A lower observed vapor pressure compared to the ideal prediction indicates a deviation from Raoult's law, often resulting from intermolecular attractions or repulsions (non-ideal behavior).
Q7. Which of the following terms represents the amount of solute dissolved in a given amount of solvent in a solution?
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Correct answer: A — Molality
Molality (moles of solute per kg of solvent) directly measures the amount of solute dissolved in a specific mass of solvent, making it a measure of concentration related to colligative properties.
Q8. In the context of Raoult's Law, if the solution is ideal, what relationship holds between the total vapor pressure (P) and the mole fraction of the solvent (Xₛₒₗᵥₑₙₜ)?
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Correct answer: B — P = Xₛₒₗᵥₑₙₜ Pₛₒₗᵥₑₙₜᵒ
For an ideal solution, the total vapor pressure is the sum of the partial pressures, which simplifies to P = Xₛₒₗᵥₑₙₜ Pₛₒₗᵥₑₙₜᵒ.
Q9. For an ideal solution of two volatile liquids, A and B, the vapor pressure of component A above the solution is directly proportional to the mole fraction of component A in the liquid phase. This relationship is described by which law?
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Correct answer: B — Raoult's Law
Raoult's Law states that the partial vapor pressure of a component in an ideal solution is equal to the mole fraction of that component in the liquid phase multiplied by its vapor pressure over the pure substance (P_A = X_A * P_A*).
Q10. If the vapor pressure of a solvent decreases upon the addition of a non-volatile solute, the process is known as:
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Correct answer: C — Vapor pressure lowering
The reduction in the vapor pressure of the solvent above the solution due to the presence of a solute is termed vapor pressure lowering.
Q11. Raoult's Law states that the partial vapor pressure of a solvent above a solution is proportional to the mole fraction of the solvent. This law is applicable to which type of solution?
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Correct answer: C — Ideal solutions
Raoult's Law is fundamentally derived for and strictly applies to ideal solutions, where intermolecular forces between components are assumed to be equal.
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