Solutions

36 solved questions from Class 12 Chemistry, each with the full working. Tap any question to see the step-by-step solution.

• 1 What is the primary chemical reaction or bonding mechanism highlighted in 'Solutions' (Class 12)? medium MCQ Reaction Mechanism & Bonding
• 2 What factor affects the rate or equilibrium constant of reactions in 'Solutions'? medium MCQ Chemical Kinetics & Factors
• 3 Which functional group or IUPAC nomenclature rule applies to compounds in 'Solutions'? medium MCQ IUPAC Nomenclature & Structure
• 4 What is the major product obtained in the characteristic reaction of 'Solutions'? medium MCQ Reaction Products & Selectivity
• 5 A solution is prepared by dissolving 0.0100 g of an unknown polymer in 20.0 mL of water at 298 K. The measured osmotic pressure of the solution is 0.085 atm. Assuming the polymer behaves as an ideal dilute solution, calculate its molar mass. hard 3 marks Osmotic pressure and molar mass determination
• 6 Calculate the boiling point elevation when 5.00 g of glucose (C_6H_12O_6, M = 180.16 g mol^-1) is dissolved in 250 g of water. The ebullioscopic constant K_b of water is 0.512 K kg mol^-1. medium 2 marks Boiling point elevation (colligative property)
• 7 Which of the following expressions correctly defines the molarity (M) of a solution? easy MCQ 1 mark Definition of molarity
• 8 Explain why a 1 mol kg^-1 aqueous solution of sucrose shows a lower vapour pressure than that predicted by Raoult's law. In your answer discuss the role of the non‑volatile solute, solute–solvent interactions, and the activity coefficient. hard 5 marks Raoult's law and deviations
• 9 A 0.0200 g sample of an unknown solute is dissolved in 50.0 mL of water. The osmotic pressure of the solution measured at 298 K is 0.120 atm. Assuming the solute behaves ideally, calculate its molar mass. hard 4 marks Osmotic pressure and molar mass
• 10 An aqueous solution containing 1.00 mol kg⁻¹ of sucrose is prepared at 25°C. The activity coefficient of sucrose is gamma = 0.95 and the vapour pressure of pure water at this temperature is 23.8 mmHg. Calculate the vapour pressure of the solution and the lowering in vapour pressure Delta P. hard 4 marks Raoult's law with activity coefficient
• 11 A solution is prepared by dissolving 2.00 g of NaCl in 500.0 mL of water at 298 K. What is the molarity of the solution? easy 2 marks Molarity calculation
• 12 Which of the following expressions gives the correct equation for the freezing point depression of an ideal dilute solution? (Choose the correct one.) medium MCQ 3 marks Freezing point depression
• 13 A sample of an unknown polymer weighing 0.0150 g is dissolved in 30.0 mL of water at 298 K. The osmotic pressure of the resulting solution is 0.142 atm. Assuming the solution behaves ideally, calculate the molar mass of the polymer. hard 3 marks Osmotic pressure and molar mass
• 14 When 4.00 g of KNO_3 is dissolved in 200 g of water, find the boiling point elevation of the solution (use K_b=0.512 K kg mol^-1 and assume KNO_3 dissociates into 2 ions). medium 2 marks Boiling point elevation
• 15 How many grams of NaOH are required to prepare 0.500 L of 3.00 M NaOH solution? easy 1 mark Molarity of a solution
• 16 Calculate the molarity of a solution prepared by dissolving 5.00 g of potassium chloride (KCl) in enough water to make 250.0 mL of solution. easy 2 marks Molarity calculation
• 17 Calcium chloride (CaCl₂) dissociates completely in water to give three ions. Calculate the freezing point depression (ΔTf) of a solution prepared by dissolving 10.0 g of CaCl₂ in 500.0 g of water. Use the cryoscopic constant of water Kf = 1.86 K·kg·mol⁻¹. hard 3 marks Freezing point depression (colligative)
• 18 A 1.20 mol·kg⁻¹ aqueous solution of sucrose at 25°C has an activity coefficient γ = 0.92. The vapor pressure of pure water at this temperature is 23.8 mmHg. Calculate (a) the vapor pressure of the solution and (b) the lowering of vapor pressure ΔP. hard 4 marks Vapour pressure lowering with activity coefficient
• 19 A sample of an unknown polymer weighing 0.0200 g is dissolved in 100.0 mL of water at 298 K. The osmotic pressure of the resulting solution is 0.120 atm. Assuming the solution behaves ideally, calculate the molar mass of the polymer. hard 3 marks Osmotic pressure and molar mass
• 20 Calculate the boiling point elevation when 5.00 g of glucose (C_6H_12O_6, M=180.16 g mol^-1) is dissolved in 250.0 g of water. The ebullioscopic constant of water is K_b=0.512 K kg mol^-1. medium 2 marks Boiling point elevation
• 21 Which of the following expressions gives the correct formula for the freezing point depression of an ideal dilute solution? medium MCQ 1 mark Freezing point depression formula
• 22 A solution is prepared by dissolving 3.50 g of sodium chloride (NaCl) in 200.0 mL of water. Calculate the molarity of the resulting solution. easy 2 marks Molarity of a solution
• 23 An aqueous solution is prepared by dissolving 8.00 g of sodium hydroxide (NaOH) in 200.0 mL of water at 298 K. Calculate the molarity of the solution. easy 2 marks Molarity calculation
• 24 A 0.0200 g sample of an unknown polymer is dissolved in 40.0 mL of water at 298 K. The osmotic pressure of the resulting solution is 0.135 atm. Assuming the solution behaves ideally, calculate the molar mass of the polymer. hard 5 marks Osmotic pressure of polymer solutions
• 25 A solution is prepared by dissolving 2.50 g of magnesium chloride (MgCl_2) in 500.0 g of water. Calculate the freezing point depression of the solution. Assume MgCl_2 dissociates completely into three ions. The cryoscopic constant of water is K_f = 1.86 K kg mol⁻¹. medium 4 marks Freezing point depression
• 26 A 0.80\;\text{mol·kg^{-1}} aqueous solution of urea at 25\;^{\circ}\text{C} shows a vapour pressure of 22.5\;\text{mmHg}. The vapour pressure of pure water at this temperature is 23.8\;\text{mmHg}. Assuming urea is a non‑volatile solute, calculate the activity coefficient \gamma_{w} of water in the solution. hard 3 marks Activity coefficient from vapour‑pressure lowering
• 27 A solution is prepared by dissolving 5.00 g of calcium chloride dihydrate (CaCl_{2}\cdot2H_{2}O, M = 147.0 g·mol^{-1}) in 200.0 g of water. Assuming complete dissociation into three ions, calculate the freezing point depression of the solution. Use the cryoscopic constant of water K_{f}=1.86\;\text{K·kg·mol^{-1}}. hard 3 marks Freezing point depression with van 't Hoff factor
• 28 Calculate the molarity of a solution prepared by dissolving 6.00 g of potassium nitrate (KNO_3, M = 101.1 g·mol^-1) in enough water to make 250.0 mL of solution at 25 °C. easy 1 mark Molarity calculation
• 29 Which of the following equations correctly represents the boiling point elevation (Δ T_b) of a dilute solution? medium MCQ 1 mark Boiling point elevation formula
• 30 A 0.0250 g sample of an unknown polymer is dissolved in 40.0 mL of water at 298 K. The osmotic pressure of the solution is measured to be 0.210 atm. Assuming ideal behaviour, calculate the molar mass (M) of the polymer. hard 4 marks Osmotic pressure and molar mass determination
• 31 Calculate the freezing‑point depression (ΔT_f) of a solution prepared by dissolving 6.00 g of aluminium sulfate octahydrate (Al₂(SO₄)₃·18H₂O, M = 666.4 g·mol⁻¹) in 250.0 g of water. Assume complete dissociation into five ions and use K_f = 1.86 K·kg·mol⁻¹ for water. medium 3 marks Freezing‑point depression with van 't Hoff factor
• 32 Calculate the molarity of a solution prepared by dissolving 8.00 g of sodium carbonate (Na₂CO₃, M = 105.99 g·mol⁻¹) in enough water to make 500.0 mL of solution at 25 °C. easy 2 marks Molarity calculation
• 33 Which of the following equations correctly represents the boiling‑point elevation (ΔT_b) of a dilute solution? medium MCQ 1 mark Boiling‑point elevation formula
• 34 A 4.00 g sample of potassium hydroxide (KOH, M = 56.11 g mol^-1) is dissolved in 300.0 g of water. Assuming KOH dissociates completely into two ions, calculate the boiling point elevation (Delta T_b) of the resulting solution. Use the ebullioscopic constant of water K_b = 0.512 K kg mol^-1. hard 5 marks Boiling‑point elevation
• 35 Which of the following expressions gives the correct formula for the lowering of vapour pressure of a dilute solution? easy MCQ 2 marks Vapour pressure lowering
• 36 A solution is prepared by dissolving 3.00 g of sodium sulfate (Na_2SO_4, M = 142.04 g mol^-1) in 250.0 g of water. Assuming Na_2SO_4 dissociates completely into three ions, calculate the freezing point depression (Delta T_f) of the solution. Use K_f = 1.86 K kg mol^-1. medium 4 marks Freezing point depression