Class 12 – Solutions (40 MCQs)
Introduction & Types of Solutions (1–4)
- A solution in which the solute completely dissociates into ions is called:
a) Saturated solution
b) Unsaturated solution
c) Electrolytic solution
d) Non-electrolyte solution - Which of the following is a gas–liquid solution?
a) Sugar in water
b) CO₂ in water
c) NaCl in water
d) Alcohol in water - A solution containing maximum solute at a given temperature is called:
a) Unsaturated
b) Saturated
c) Supersaturated
d) Dilute - Which of the following is true for a dilute solution?
a) Solute >> solvent
b) Solvent >> solute
c) Solute = solvent
d) None of the above
Concentration Terms (5–11)
- Molarity is defined as:
a) Moles of solute per kg of solvent
b) Moles of solute per litre of solution
c) Moles of solute per mole of solvent
d) Mass of solute per litre of solution - Molality is defined as:
a) Moles of solute per kg of solvent
b) Moles of solute per litre of solution
c) Mass of solute per kg of solvent
d) Mole fraction of solute - Mole fraction of solute is:
a) n_solute / n_solvent
b) n_solute / (n_solute + n_solvent)
c) n_solvent / (n_solute + n_solvent)
d) Mass_solute / Mass_solvent - ppm refers to:
a) Parts per million by mass
b) Parts per thousand
c) Parts per billion
d) Parts per mole - Normality (N) is defined as:
a) Moles of solute per litre
b) Gram equivalent of solute per litre of solution
c) Mass fraction of solute
d) Mole fraction of solute - If 1 mole of solute is dissolved in 1 L of solution, the molarity is:
a) 0.5 M
b) 1 M
c) 2 M
d) 1.5 M - Mole fraction is always:
a) >1
b) <1
c) =1
d) 0
Raoult’s Law & Ideal Solutions (12–17)
- Raoult’s law states that the partial vapor pressure of a component in a solution is:
a) Equal to its mole fraction × vapor pressure of pure component
b) Equal to vapor pressure of pure component
c) Independent of mole fraction
d) Equal to solubility - For ideal solutions:
a) ΔH_mix = 0, ΔV_mix = 0
b) ΔH_mix > 0
c) ΔV_mix > 0
d) ΔH_mix < 0 - Which of the following is an ideal solution?
a) Benzene + Toluene
b) Water + Ethanol
c) NaCl + H₂O
d) HCl + H₂O - Raoult’s law is obeyed by:
a) Strong electrolytes
b) Ideal solutions
c) Non-volatile solutes only
d) Saturated solutions - Partial vapor pressure of solvent A in solution depends on:
a) Mole fraction of solute only
b) Mole fraction of solvent × P⁰_A
c) Mass of solvent
d) Volume of solution - Which of the following causes positive deviation from Raoult’s law?
a) Strong solute–solvent interactions
b) Weak solute–solvent interactions
c) Ideal mixing
d) None
Colligative Properties (18–29)
- Colligative properties depend on:
a) Nature of solute
b) Amount of solute particles
c) Solvent type only
d) Pressure - Lowering of vapor pressure by a non-volatile solute is called:
a) Boiling point elevation
b) Freezing point depression
c) Relative lowering of vapor pressure
d) Osmotic pressure - Boiling point elevation is:
a) ΔT_b ∝ moles of solute
b) ΔT_b ∝ molality of solute
c) ΔT_b ∝ mole fraction
d) ΔT_b independent - Freezing point depression depends on:
a) Molality of solute
b) Mass of solvent
c) Volume of solution
d) Pressure - Osmotic pressure is given by:
a) π = MRT
b) π = ΔT × K_f
c) π = ΔT × K_b
d) π = 1/RT - Which of the following is not a colligative property?
a) Osmotic pressure
b) Freezing point depression
c) Molarity
d) Boiling point elevation - Van’t Hoff factor (i) accounts for:
a) Molecular mass
b) Dissociation or association of solute
c) Solvent boiling point
d) None - For NaCl in water, i ≈:
a) 1
b) 2
c) 3
d) 0 - Colligative property depends on:
a) Mass fraction of solute
b) Number of particles in solution
c) Chemical nature
d) Color - Which has higher boiling point elevation: 1 mol of NaCl or 1 mol of glucose in 1 kg water?
a) NaCl
b) Glucose
c) Both same
d) Cannot say - Freezing point of 1 m NaCl solution is lower than that of 1 m sugar solution because:
a) NaCl dissociates into ions
b) Sugar is non-volatile
c) Sugar does not affect freezing
d) NaCl forms complex - Boiling point elevation constant for water is:
a) 0.512 K kg/mol
b) 0.512 K/m
c) 1.86 K kg/mol
d) 1.86 K/m
Molecular Mass Determination (30–33)
- Molecular mass can be determined by:
a) Osmotic pressure
b) Freezing point depression
c) Boiling point elevation
d) All of the above - A solution shows a freezing point depression of 1.86 K. Molality of solute is 1 m. Molecular weight of solute is:
a) 100 g/mol
b) 50 g/mol
c) 200 g/mol
d) 25 g/mol - Determination of molecular mass using colligative property is useful for:
a) Electrolytes only
b) Non-electrolytes only
c) Both electrolytes and non-electrolytes
d) None - Which colligative property is most accurate for molecular mass determination?
a) Vapor pressure lowering
b) Osmotic pressure
c) Freezing point depression
d) Boiling point elevation
Non-ideal Solutions & Deviations (34–37)
- Positive deviation from Raoult’s law occurs due to:
a) Weak solute–solvent interactions
b) Strong solute–solvent interactions
c) Ideal mixing
d) None - Negative deviation occurs when:
a) Solute–solvent attraction < solute–solute/solvent–solvent
b) Solute–solvent attraction > solute–solute/solvent–solvent
c) Solute is non-volatile
d) Solvent is volatile - Azeotropes are:
a) Ideal solutions
b) Constant boiling mixtures
c) Dilute solutions
d) Electrolytic solutions - Which of the following solutions is ideal?
a) Ethanol + water
b) Benzene + Toluene
c) HCl + water
d) Acetic acid + water
Conceptual / Application-Based (38–40)
- Osmosis occurs due to:
a) Solvent movement from dilute to concentrated solution
b) Solute movement
c) Vapor pressure lowering
d) Boiling point elevation - Reverse osmosis is used for:
a) Desalination of water
b) Molality determination
c) Vapor pressure measurement
d) Freezing point depression - Colligative properties are independent of:
a) Number of solute particles
b) Chemical nature of solute
c) Molality of solute
d) Van’t Hoff factor
Answer Key – Class 12 Chemistry: Solutions (40 MCQs)
Introduction & Types of Solutions (1–4)
- c) Electrolytic solution – Solute dissociates into ions.
- b) CO₂ in water – Gas dissolved in liquid.
- b) Saturated – Maximum solute at a given temperature.
- b) Solvent >> solute – In dilute solutions, solvent is much more than solute.
Concentration Terms (5–11)
- b) Moles of solute per litre of solution – Definition of molarity (M).
- a) Moles of solute per kg of solvent – Definition of molality (m).
- b) n_solute / (n_solute + n_solvent) – Mole fraction formula.
- a) Parts per million by mass – ppm definition.
- b) Gram equivalent of solute per litre of solution – Normality definition.
- b) 1 M – 1 mole in 1 litre = 1 mol/L.
- b) <1 – Mole fractions always <1.
Raoult’s Law & Ideal Solutions (12–17)
- a) Equal to its mole fraction × vapor pressure of pure component – Raoult’s law.
- a) ΔH_mix = 0, ΔV_mix = 0 – Ideal solution behavior.
- a) Benzene + Toluene – Similar intermolecular forces → ideal.
- b) Ideal solutions – Obey Raoult’s law.
- b) Mole fraction of solvent × P⁰_A – Partial vapor pressure formula.
- b) Weak solute–solvent interactions – Causes positive deviation.
Colligative Properties (18–29)
- b) Amount of solute particles – Colligative properties depend only on particle number.
- c) Relative lowering of vapor pressure – Colligative property.
- b) ΔT_b ∝ molality of solute – Boiling point elevation formula: ΔT_b = K_b·m·i.
- a) Molality of solute – Freezing point depression formula: ΔT_f = K_f·m·i.
- a) π = MRT – Osmotic pressure formula.
- c) Molarity – Not a colligative property.
- b) Dissociation or association of solute – Van’t Hoff factor i.
- b) 2 – NaCl dissociates into 2 ions (Na⁺, Cl⁻).
- b) Number of particles in solution – Colligative properties depend on particle count.
- a) NaCl – More particles → greater effect.
- a) NaCl dissociates into ions – More particles → larger ΔT_f.
- c) 1.86 K kg/mol – Freezing point depression constant (K_f) for water.
Molecular Mass Determination (30–33)
- d) All of the above – Molecular mass can be determined using any colligative property.
- b) 50 g/mol – Using ΔT_f = K_f·m → moles → molar mass.
- b) Non-electrolytes only – Dissociation complicates calculations.
- b) Osmotic pressure – Most accurate for molecular mass determination.
Non-Ideal Solutions & Deviations (34–37)
- a) Weak solute–solvent interactions – Causes positive deviation.
- b) Solute–solvent attraction > solute–solute/solvent–solvent – Causes negative deviation.
- b) Constant boiling mixtures – Definition of azeotropes.
- b) Benzene + Toluene – Ideal solution example.
Conceptual / Application-Based (38–40)
- a) Solvent movement from dilute to concentrated solution – Definition of osmosis.
- a) Desalination of water – Reverse osmosis application.
- b) Chemical nature of solute – Colligative properties are independent of solute type.
Disclaimer:
All MCQs on this page are created for educational purposes only. They are intended for practice and NEET/Class 12 Chemistry preparation and do not guarantee any specific exam results.