CBSE Class 12 Chemistry – Chapter 2: Solutions

Vocabulary flashcards covering definitions and fundamental terms from CBSE Class 12 Chemistry Chapter 2 – Solutions.

Solution

A homogeneous mixture formed by combining two or more substances in any physical state.

Solvent

The component of a solution present in the larger amount; it dissolves the solute.

Solute

The component of a solution present in the smaller amount and dissolved by the solvent.

Binary Solution

A solution containing exactly two components—a solute and a solvent.

Aqueous Solution

A solution in which water acts as the solvent.

Non-Aqueous Solution

A solution whose solvent is any liquid other than water.

Unsaturated Solution

A solution capable of dissolving additional solute at a given temperature.

Saturated Solution

A solution that cannot dissolve more solute at a specified temperature.

Supersaturated Solution

A metastable solution containing more dissolved solute than a saturated solution at the same temperature.

Solubility

The maximum amount of solute that dissolves in 100 g of solvent at a given temperature.

Henry’s Law

At constant temperature, the partial pressure of a gas above a liquid is directly proportional to its mole fraction in the solution.

Dilute Solution

A solution with a relatively small amount of solute compared to solvent.

Concentrated Solution

A solution containing a relatively large amount of solute with respect to solvent.

Percentage by Weight (w/w %)

Mass of solute per 100 g of solution, expressed as a percentage.

Percentage by Volume (w/V %)

Mass or volume of solute per 100 mL of solution, given as a percentage.

Mole Fraction (x)

The ratio of moles of a component to the total moles of all components in the solution.

Parts Per Million (ppm)

Number of parts of solute per one million parts of solution; used for trace concentrations.

Molarity (M)

Moles of solute per litre of solution.

Molality (m)

Moles of solute per kilogram of solvent.

Normality (N)

Gram-equivalents of solute per litre of solution.

Formality (F)

Formula​ weights of solute per litre of solution; similar to molarity for ionic salts.

Mass Fraction

Mass of a component divided by total mass of the solution.

Demal (D)

Concentration equal to one mole of solute per litre of solution at 0 °C.

Raoult’s Law

The relative lowering of vapour pressure of a solvent equals the mole fraction of the non-volatile solute.

Ideal Solution

A solution that obeys Raoult’s Law over the entire composition range because solute–solvent interactions equal solvent–solvent and solute–solute interactions.

Positive Deviation

Condition where a solution’s vapour pressure is higher than predicted by Raoult’s Law due to weaker solute–solvent interactions.

Negative Deviation

Condition where a solution’s vapour pressure is lower than predicted by Raoult’s Law owing to stronger solute–solvent interactions.

Konowaloff’s Rule

At a fixed temperature, the vapour phase is richer in the more volatile component than the liquid phase of the same solution.

Colligative Properties

Solution properties that depend only on the number of solute particles, not their nature (e.g., ΔTb, ΔTf, osmotic pressure).

Relative Lowering of Vapour Pressure

A colligative property given by (P° − P)/P° and equal to the mole fraction of the solute.

Elevation of Boiling Point (ΔTb)

Increase in boiling point proportional to molality: ΔTb = Kb m.

Depression of Freezing Point (ΔTf)

Decrease in freezing point proportional to molality: ΔTf = Kf m.

Osmotic Pressure (π)

Pressure required to stop osmosis; given by π = CRT for dilute solutions.

Cryoscopic Constant (Kf)

Proportionality constant used in freezing-point depression calculations.

Ebullioscopic Constant (Kb)

Proportionality constant used in boiling-point elevation calculations.