Assignment Solution PDF

# ASSIGNMENT SOLUTION ## What is binary solution? ## Method of expressing concentration of solution: 1. 20 g of glucose was dissolved in 200 g of water. Find the mass percentage of glucose in the solution. 2. A sample of hard water was found to contain 40 mg of MgSO4 in 10 kg of sample. Calculate...

# ASSIGNMENT SOLUTION ## What is binary solution? ## Method of expressing concentration of solution: 1. 20 g of glucose was dissolved in 200 g of water. Find the mass percentage of glucose in the solution. 2. A sample of hard water was found to contain 40 mg of MgSO4 in 10 kg of sample. Calculate the ppm of MgSO4 in the sample. 3. 15 tons of the air has 0.03g of the carbon as smoke. Calculate the ppm of carbon in air. 4. The percentage composition (by weight) of a solution is 45% X, 15% Y and 40% of Z, calculate the mole fraction of each component of the solution. (Molecular mass of X = 18, Y = 60 and Z= 60) 5. Calculate the molarity of pure water (density 1 g/m L). 6. A 6.90 M solution of KOH in water contains 30% by mass of KOH. Calculate the density of the KOH solution? (Molar mass of KOH = 56 g mol¹) 7. Calculate the molality of a solution of ethanol which contains 15.87g of ethanol (C2H5OH) in 168g of water. 8. The given sample of sulphuric acid was found to have fraction of H₂SO₄ as 0.15. Calculate the molality of the solution. 9. Calculate the number of moles of methanol in 5 litres of its 2 m solution, if the density of the solution is 0.981 kg L¹. Molar mass of methanol = 32.0 g mol¹. 10. Calculate the molality of a solution of 93% H2SO4 (w/v) when the density of solution is 1.84 g cm³. At. Masses: S=32, O 16, H = 1 amu. 11. The molarity of a solution of sulphuric acid is 1.35 M. Calculate its molality. Calculate its molality (The density of the acid solution is 1.02 g cm³³). 12. Calculate the molarity and molality of a 13% solution (by weight) of sulphuric acid. Its density is 1.020 g cm³. Atomic masses: H = 1, O = 16, S=32 amu. 13. How much of NaOH is present in 100 mL (N) solution. 14. How much of Na2SO3 is required to prepare 2 litres of N/10 solution? 15. 4.9 gram of H₂SO₄ is dissolved in water to make it 500 ml of solution. Find out the normality of solution. 16. A syrup is prepared by dissolving 250g sucrose in 150g of water. Calculate the mass per cent sucrose in solution. (Ans :62.5%) 17. What is the molality of ammonia in a solution containing 0.85 g of NH3 in 100 ml of a liquid of density 0.85 g cm³³? (Ans: 0.59m) 18. 4.0 g of NaOH is contained in one deciliter of a solution. Calculate molality of solution and mole fraction of NaOH. (Density of solution is 1.08 g cm³). (Ans: 1.002 m, 0.017) 19. Calculate the amount of oxalic acid [(COOH)2.2H2O)] in gram that is required to obtain 250 mL of a semi-molar (M/2) solution. 20. Calculate the mole fraction of ethylene glycol (C2H6O2) in a solution containing 20% of C2H6O2 by mass. (Ans: 0.068) 21. Calculate the molarity of a solution containing 5g of NaOH in 450 mL solution. 22. Calculate molality of 2.5g of ethanoic acid (CH3COOH) in 75 g of benzene. (Ans: 0.556 mol kg¹) 23. How much of NaOH is present in 2 Litre of N/10 solution? (Ans - 8 gm) 24. How will you prepare 5 litres of N/10 solution of HCI? 25. What is normality of the Na2CO3 solution if 250 ml of N/2 is diluted to 1 litre? 26. How much of KOH is required to prepare 500 ml of N/2 solution? 27. 50 ml of N/2 HCI solution is mixed with 50 ml of N/10 NaOHsolution, what is the normality of resulting solution? 28. Find out the normality of resulting solution obtained by mixing 50 ml of N/10 HCI, 501 of N/2 HCI and 100 ml of N/20 HCI. ## Solubility: Henery's law & its application. 1. The Henry law constant for H2(g) in water is 5.34×10' torr. Calculate the solubility of this gas in water at 298 K if its partial pressure over the solution is 760 torr. Assume that the density of the solutions the same as the density of the solvent. 2. If N₂ gas is bubbled through water at 293 K, how many milimoles of N₂ gas would dissolve in 1 litre of water? Assume that N₂ exerts a partial pressure of 0.987 bar. Given that Henry's law costant for N2 at 293 K is 76.48 bar. (Ans-0.716 m mol) 3. The KH values of He, H₂ and N₂ at 293 K in water are 10.9×10 and 5.72×10' torr respectively. What inference can you draw about their solubility in water? 4. A soda-water bottle was opened and the soft drink allowed to come to equilibrium at 298 K with air containing CO2 gas at a pressure of 4.0×10 atm. Find the concentration of CO2 gas in the soda after it had stood open and come to equilibrium. The Henry's constant for aqueous solution of CO2 at 298 K is 3.2×10-2 mol litre 'atm¹ (Ans: 1.3 × 105 mol litre-¹] ## Raoult's law, Ideal & non-ideal solution, azeotropic mixture 1. Write difference between ideals & non ideal solution. 2. What are the two types of denation shown by non-ideal solution. Give one example of it. 3. What is azeotropic mixture. Give one example of it. 4. What is the similarity & difference between Raoult's law & Henry's law. 5. Explain any a solution of chloroform & acetone shown negative deviation from Raoult's law. 6. No.-Ideal solution exhibit ether positive or negative deviation from Raoult's law. What are these deviation & Why are they caured? Explain with one example of each types. ## Calligative properties & Van't Hoff factor: 1. The vapour pressure of pure water at 298 K is 23.8 mmof Hg. 50 gof urea is dissolved in 850 g of water. Calculate the V.P. of water for this solution & its relative lowering. 2. The osmotic pressure of a solution containing 50g of solute in one litre of solution at 300 K is 20.5 atm. Calculate the molecular mass of solute. 3. The boiling point of water is 100°C. Calculate the boiling point of an aqueous solution containg 5g urea in 100 g of water. (Kb for water 0.52 K Ka mol¹) 4. The boling point of benzene is 353.2 K. When 1.8 g of non volatile solute was dissolved in 90 g of benzene the boiling point was raised to 354.1 K. Calculate the molecular mss of the solute. (Kb the benzene = 2.53 K m²¹) 5. Calculate the boiling point of a solution containing 0.456 g of camphor (Molecular mass 152) dissolved in 31.4 g acetone (boiling point = 56.3°), the molecular elevation constant per 100 g of acetone is 17.2°C. 6. Find the freezing point of solution containg 0.52 g of glucose dissolved in 80.2 g of water (Given, Kf for water = 1.36 Km²¹) 7. Calculate the amount of KCI which must be added to 1 Kg of water so the freezing point is depressed by 2 K. (Kf for water = 1.36 k Kg mol¹) 8. A 0.56 m solution of unknown electrolyte depresses the freezing point of water by 2.93°C. What is van't hoff factor for this electrolyte? (Kf for water = 1.86°C kg mol¹) 9. What mass of nail must be dissolved in 65.0 g of water to lower the freezing point of water by 7.50°C ? Assumed Van't Hoff factor for Nail is 1.87. (Kf for water = 1.86° c/m. 10. What mass of ethylene glycol (molar mass 62.0 g mol¹) must be added to 5.50 kg of water to lower the freezing point of water from 0°C to -10°C? (Kf for water = 1.86 K Kg mol¹) 11. What is Van't Hoff factor? How does it help in calculating degree of association & dissociation. ## 7 Marks: 1. State Rault's law. How is the molecular mass of solute determined from lowering of vapour pressure. Measurement? 2. Write how will you calculate the molecular mass of a non-volatile solute from elevation of boiling point measurement. 3. Write how will you calculate the molecular mass of a non-volatile solute from depression of freezing point measurement. 4. What is Raoult's law? What are the two types of deviation shown by non ideal solution. Explain with example.