1. Types of Solutions
Q1. What are binary solutions?
A1. Solutions with two components are called binary solutions.
Q2. What is the difference between solid in liquid and gas in liquid solutions?
A2. In solid in liquid solutions, a solid solute dissolves in a liquid solvent (e.g., sugar in water), while in gas in liquid, a gas solute dissolves in a liquid solvent (e.g., CO₂ in soda).
2. Expressing Concentration of Solutions
Q1. What are the different methods of expressing concentration of a solution?
A1. Concentration can be expressed as mass percent, volume percent, mole fraction, molarity, and molality.
Q2. How is molarity defined?
A2. Molarity is the number of moles of solute dissolved in one litre of solution.
Q3. What is the unit of molality?
A3. Molality is expressed in mol/kg.
3. Solubility
Q1. What is solubility?
A1. Solubility is the maximum amount of a substance that can be dissolved in a given amount of solvent at a specific temperature.
Q2. What factors affect solubility?
A2. Solubility is affected by temperature, nature of solute and solvent, and pressure (in the case of gases).
4. Solubility of Gases in Liquids – Henry’s Law
Q1. What does Henry's Law state?
A1. Henry’s Law states that the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid.
Q2. Why do scuba divers use a mixture of oxygen and helium?
A2. To avoid the toxic effects of high nitrogen concentration under pressure, helium is used to dilute the oxygen.
5. Vapour Pressure of Liquid Solutions
Q1. What is Raoult’s Law?
A1. Raoult’s Law states that the partial vapour pressure of each volatile component in a solution is directly proportional to its mole fraction.
Q2. How does vapour pressure vary in ideal solutions?
A2. In ideal solutions, vapour pressure varies linearly with mole fraction.
6. Ideal and Non-Ideal Solutions
Q1. What characterizes an ideal solution?
A1. An ideal solution obeys Raoult’s Law at all concentrations and shows no change in enthalpy or volume upon mixing.
Q2. Give an example of a non-ideal solution with negative deviation.
A2. A mixture of acetone and chloroform shows negative deviation due to hydrogen bonding.
7. Colligative Properties
Q1. What are colligative properties?
A1. Colligative properties depend on the number of solute particles, not their nature.
Q2. Name the four colligative properties.
A2. Relative lowering of vapour pressure, elevation of boiling point, depression of freezing point, and osmotic pressure.
8. Determination of Molar Mass using Colligative Properties
Q1. How can molar mass be determined using freezing point depression?
A1. By measuring the depression in freezing point and using the formula involving the cryoscopic constant.
Q2. What is the van’t Hoff factor?
A2. It is the ratio of the observed colligative property to the calculated one, accounting for dissociation or association.
9. Abnormal Molar Masses
Q1. What causes abnormal molar masses?
A1. Association or dissociation of solute molecules in solution leads to abnormal molar masses.
Q2. How does the van’t Hoff factor correct for abnormal molar masses?
A2. It adjusts the calculated molar mass by considering the actual number of particles in solution.
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