What is the relation between molar mass of solute and boiling point elevation of solution?
M2 = \(\frac {1000\ △T_bW_2}{K_bW_1}\)
M2 = \(\frac {1000\ K_bW_2}{△T_bW_1}\)
M2 = \(\frac {△T_bW_1}{1000\ K_bW_2}\)
M2 = \(\frac {1000\ K_bW_1}{△T_bW_2}\)
The relation between the molar mass of the solute (M2) and the boiling point elevation of the solution (△Tb) can be given by the equation:
△Tb = \(\frac {K_b . M_2 . W_2}{W_1}\)
where:
△Tb is the boiling point elevation of the solution,
Kb is the molal boiling point elevation constant,
M2 is the molar mass of the solute,
W2 is the weight (mass) of the solute,
and W1 is the weight (mass) of the solvent.
To convert the equation into a more convenient form, we can multiply both sides by 1000:
1000 . △Tb = \(\frac {1000 .K_b . M_2 .W_2}{W_1}\)
Simplifying, we have:
M2 = \(\frac {1000 . K_b . W_2}{△T_b . W_1}\)
We can see that the correct relation is option (B): M2 = \(\frac {1000 . K_b . W_2}{△T_b . W_1}\)
According to the generally accepted definition of the ideal solution there are equal interaction forces acting between molecules belonging to the same or different species. (This is equivalent to the statement that the activity of the components equals the concentration.) Strictly speaking, this concept is valid in ecological systems (isotopic mixtures of an element, hydrocarbons mixtures, etc.). It is still usual to talk about ideal solutions as limiting cases in reality since very dilute solutions behave ideally with respect to the solvent. This law is further supported by the fact that Raoult’s law empirically found for describing the behaviour of the solvent in dilute solutions can be deduced thermodynamically via the assumption of ideal behaviour of the solvent.
Answer the following questions:
(a) Give one example of miscible liquid pair which shows negative deviation from Raoult’s law. What is the reason for such deviation?
(b) (i) State Raoult’s law for a solution containing volatile components.
OR
(ii) Raoult’s law is a special case of Henry’s law. Comment.
(c) Write two characteristics of an ideal solution.