In both the components, water (A component) and alcohol (B component), the molecules are hydrogen bonded, i.e., A-A as well as B-B interactions are mainly H-bonds forces. When these two components are mixed to form the solution, due to molecular collisions A-A and B-B interactions are broken down and new interactions of the type A-B are formed. A-B interactions are also mainly H-bonds i.e., the molecules of one liquid will tend to break the hydrogen bonds in the molecules of other liquid and vice-versa. A-B interactions formed will be weaker than A-A and B-B types of of interactions as the alcohol and water solution show positive deviation and it will lead to increase in volume (ΔVmix is + ve).
Molarity (M) is defined as number of moles of solute dissolved in one litre (or one cubic decimetre) of solution.
(a) Mol. mass of
Volume of solution = 4.3 L
(b) Number of moles present in 1000 ml of 0.5M H2SO4= 0.5 mol
therefore number of moles present in 30ml of 0.5M H2SO4=mol =0.015mol
therefore molarity =0.015/0.5L
thus molarity is 0.03M
Molality (m) is defined as the number of moles of the solute per kilogram (kg) of the solvent and is expressed as:
Calculate (a) molality (b) molarity and (c) mole fraction of KI if the density of 20% (mass/mass) aqueous KI is 1.202 g mL-1.