NEET UG - Concentration expressions: molality molarity mole fraction percentage by volume and mass One Line Questions & Answers

1. Percentage by mass of a component in a solution is defined as: — (Mass of solute / Mass of solution) * 100

2. What is percentage by volume (v/v) defined as? — (Volume of solute / Volume of solution) * 100

3. If 1 mole of NaCl (molar mass = 58.44 g/mol) is dissolved in 100 g of water, what is the molality? — 10 m

4. If 18 g of glucose (molar mass = 180 g/mol) is dissolved in 100 g of water, what is the molality? — 1 m

5. What is the mole fraction of solute if the solution is 20% by mass of NaCl (molar mass = 58.5 g/mol) in water? — 0.039

6. What is the mole fraction of the solvent if the mole fraction of the solute is 0.2? — 0.8

7. If 1 mole of a solute is dissolved in 250 g of solvent, what is the molality of the solution? — 4 m

8. What is the mole fraction of water in a solution containing 9 g of water (molar mass = 18 g/mol) and 18 g of ethanol (molar mass = 46 g/mol)? — 0.625

9. If 1 mole of solute is dissolved in 500 mL of solution, what is the molarity? — 2 M

10. If a solution has a molarity of 0.5 M and a density of 1.05 g/mL, what is its approximate molality? — 0.476 m

11. A solution contains 3 moles of solute and 9 moles of solvent. What is the mole fraction of the solvent? — 0.75

12. If 22.4 L of a gas at STP is dissolved in 1 L of solvent, the molarity is approximately: — 1 M

13. If 1 mole of solute is dissolved in 1 kg of solvent, what is the molality of the solution? — 1 m

14. What is the molality of a 1.0 M aqueous solution of NaCl (density = 1.05 g/mL, molar mass of NaCl = 58.5 g/mol)? — 0.93 m

15. If a solution is 10% (w/w) ethanol and its density is 0.98 g/mL, what is its molarity? — 1.68 M

16. If a solution is 10% (w/v) glucose, it means: — 10 g of glucose in 100 mL of solution

17. A solution of 10% (v/v) acetic acid in water means: — 10 mL of acetic acid in 100 mL of solution

18. If 10 g of NaOH is dissolved in 90 g of water, what is the mass percentage of NaOH? — 10%

19. A solution has a molarity of 2 M. What does this mean? — 2 moles of solute are present in 1 liter of solution

20. If a solution contains 2 moles of solute A and 3 moles of solvent B, what is the mole fraction of solute A? — 2/5

21. If a solution is prepared by mixing 20 mL of ethanol with 80 mL of water, what is the percentage by volume of ethanol? — 20%

22. If 100 mL of a solution contains 5 g of NaOH, what is the concentration in g/L? — 50 g/L

23. A solution is prepared by dissolving 5 g of NaCl in 45 g of water. What is the mass percentage of NaCl? — 10%

24. Consider a solution of ethanol in water. If the percentage by volume is 50%, it means: — 50 mL of ethanol in 100 mL of solution

25. Percentage by volume is used when: — Both solute and solvent are liquids

26. When is percentage by mass (w/w) most commonly used? — For solid solutions and concentrated liquid solutions

27. What is the primary advantage of using molality over molarity? — It is independent of temperature

28. Molarity is defined as the number of moles of solute per: — Liter of solution

29. The sum of mole fractions of all components in a solution is always: — Equal to 1

30. If the molar mass of a solute is M and its molality is m, what is the mass of the solute in 1 kg of solvent? — m * M

31. What is the relationship between molarity (M), density (d), and mass percentage (w/w) of a solution? — M = (1000 * d * w/w) / (100 * Molar Mass + w/w)

32. If the molarity of a solution is M, and the density is d (in g/mL), and the molar mass of the solvent is M_solvent, what is the molality (m)? — m = (1000 * M) / (1000 * d - M * M_solute)

33. What is the relationship between molarity (M) and molality (m) for a dilute aqueous solution? — M > m

34. What is the unit of molarity? — mol/L

35. What is the unit of molality? — mol/kg

36. Which concentration expression is most useful for expressing the concentration of gases dissolved in liquids? — Mole fraction

37. Which concentration unit is most convenient for stoichiometric calculations in solution reactions? — Molarity

38. Which concentration unit changes with temperature? — Molarity

39. What is the primary difference between molality and molarity in terms of the denominator? — Molality uses mass of solvent, Molarity uses volume of solution

40. Which concentration unit is most appropriate for expressing the concentration of a very dilute solution of a pollutant in water? — Parts per million (ppm)

41. Which concentration expression is directly proportional to the mole fraction of the solute? — None of the above

42. Which of the following concentration units is dimensionless? — Mole fraction

43. Which concentration expression is most directly related to the partial pressure of a gaseous solute in a liquid solution according to Henry's Law? — Mole fraction

44. Which concentration unit is often used for very low concentrations of dissolved solids in liquids? — Parts per billion (ppb)

45. If 1 mole of solute is dissolved in 1 liter of solvent, which concentration expression is it? — None of these

46. Which concentration unit is independent of temperature? — Molality

47. For a dilute solution, which concentration expression is most suitable for expressing the amount of solute? — Parts per million (ppm)

48. What is molality defined as? — Moles of solute per kilogram of solvent

49. What is mole fraction of a component in a solution? — Moles of solute / Moles of solution

50. What does 'ppm' stand for in concentration expressions? — Parts per million

Concentration expressions: molality molarity mole fraction percentage by volume and mass - One Line Questions