Water phase change in soil causes severe damage to roads, canals, airport runways and other…
Chemistry20255 marksCase based
Water phase change in soil causes severe damage to roads, canals, airport runways and other buildings. The freezing point is an important indicator to judge whether the soil is frozen or not. It is found that the addition of salt can effectively reduce the frost heave of soil.
The graphs given below show the change in freezing point with different concentrations of salt and water:
Source: https://www.mdpi.com/2073-4441/12/8/2232
It is clear from the graphs that as water content is high, depression is less and as the salt concentration is high, depression is more.
(a)[2.0]
2.1g $\text{CoCl}_3\cdot 6\text{NH}_3$ (molecular weight = 267.5) was dissolved in 100 g of water. The freezing point of the solution was $-0.584^\circ\text{C}$. Assuming 100% ionization of the complex salt having coordination number 6, what will be the formula of the complex.
Given that: $K_f$ for water = $1.86\text{ K kg mol}^{-1}$.
(b)[1.5]
Which salt solution is the best for de-icing?
1% NaCl or 1% $\text{CaCl}_2$
[Atomic weight of Na= 23, Ca = 40, Cl = 35.5 a.m.u]
(c)[1.5]
Equimolal concentration of two different solutes X and Y undergoes dimerization and trimerization respectively in their respective solutions. What will be the ratio of observed lowering of vapour pressure in two cases?
