is .24K obtained by dissolving 1g NaCl in 200g water. Calculate van’t-Hoff factor. The molal depression constant is . K Kg mol - Molar mass of solute × K f × mass of NaCl ΔT f × mass of solvent × .
× . × .75g mol - . g mol - Theoretical molar mass of NaCl is = Theoretical molar mass Experimental molar mass i . .
m aqueous solution of KCl freezes at - . º C calculate van’t Hoff factor. k f for water is . K kg mol - .
Evaluate Yourself Unit Unit - - - - SUMMARY • A solution is a homogeneous mixture of two or more chemically non- reacting substances mixed uniformly. The proportion of component which is more in the solution is called solvent and the lesser component is called solute. • The different concentration units used to prepare the solutions are formality, molality , normality, molarity, molefraction, %w/w solution, %w/v solution, %v/v solution. If the solute quantity is very minimum then ppm unit is used to express its concentration.
• The standard solutions are prepared and diluted to desired concentration (working standards). This helps in overcoming the error due to weighing and maintain efficiency and consistency in the preparation of solution. • Solubility is defined as the amount of solute in a saturated solution per 100g of a solvent. Solubility of a solute in a solvent depends on the nature of the solute and solvent , temperature.
• The solubility of a gas in a liquid depends upon, the nature of the gas and the nature of the liquid, the temperature of the system, and the pressure of the gas. • The effect of pressure on the solubility of a gas in a liquid is governed by Henry’s Law. It states that the solubility of a gas in a liquid at a given temperature in directly proportional to the partial pressure of the gas. • The vapour pressure of a liquid is the pressure exerted by its