Solutions NIOS Intext Questions With Answer
National Institute of Open Schooling (NIOS)
Sr. Secondary, Module-3
Lession-7: Solutions NIOS Intext Questions With Answer
INTEXT QUESTIONS 7.1
1. List the various methods of expressing the concentration of a solution ?
Answer: Molarity, molality, normality, mole fraction and mass percentage are the various methods used to express the concentration of a solution.2. Define the following-
Molarity, Molality and Normality
Answer: Molarity is the number of moles of solute dissolved per litre of the solution.Molality is the number of moles of solute dissolved per kg of solvent.
Normality is the number of gram equivalents of solute dissolved per litre of solution.
INTEXT QUESTIONS 7.2
1. State Raoult’s law.
Answer: For a solution of volatile liquids, the partial vapour pressure of each liquid is proportional to its mole fraction.2. State Henry's law and list the conditions necessary for the validity of Henry's law.
Answer: The mass of a gas dissolved in a solvent is directly proportional to its partial pressure at constant temperature.P ∝ C
P = kH.C
Where,
'P' denotes the partial pressure of the gas in the atmosphere above the liquid. 'C' denotes the concentration of the dissolved gas. 'kH' is the Henry's law constant of the gas.
Necessary conitions for the validity of Henry's law-
Pressure should not be too high
Temperature should not be too low
The gas should not associate or dissociate.
INTEXT QUESTIONS 7.3
1. Define colligative property. List two colligative properties.
Answer: Properties that depend upon the number of particles of solute and not on the nature of solute is called Colligative property. Elevation of boiling point, depression of freezing point are the two examples of colligative properties.2. What type of liquid pairs show (i) positive deviations (ii) negative deviations.
Answer:For which A–B molecular interactions are-weaker than A–A and B–B interactions
stronger than A–A and B–B interactions.
