Embibe Experts Solutions for Chapter: Solutions, Exercise 3: EXERCISE-3

The freezing point of ether was lowered by $0.60°\mathrm{C}$ on dissolving $2.0 \mathrm{g}$ of phenol in $100 \mathrm{g}$ of ether. Calculate the molar mass of phenol and comment on the result. Given : ${\mathrm{K}}_{\mathrm{f}}$ (ether) $=5.12 \mathrm{K} \mathrm{kg}{ \mathrm{mol}}^{-1}$.

The addition of $3 \mathrm{g}$ of a substance to $100 \mathrm{g} {\mathrm{CCl}}_4\left(\mathrm{M}=154 \mathrm{g}{ \mathrm{mol}}^{-1}\right)$ raises the boiling point of ${\mathrm{CCl}}_4$ by $0.60°\mathrm{C}$. If ${\mathrm{K}}_{\mathrm{b}}\left({\mathrm{CCl}}_4\right)$ is $5 \mathrm{K}{ \mathrm{mol}}^{-1} \mathrm{kg}$, calculate the freezing point depression.
Given : ${\mathrm{K}}_{\mathrm{f}}\left({\mathrm{CCl}}_4\right)=32.0 \mathrm{K} \mathrm{kg}{ \mathrm{mol}}^{-1}$.

To $500 \mathrm{gm}$ of water $3.0\times {10}^{-3} \mathrm{kg}$ of acetic acid is added. If $23\%$ of acetic acid is dissociated, what will be the depression of freezing point? ${\mathrm{K}}_{\mathrm{f}}=1.86 \mathrm{K} \mathrm{kg}{ \mathrm{mol}}^{-1}$.

$0.01 \mathrm{m}$ aqueous solution of ${\mathrm{K}}_3\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$ freezes at $-0.062°\mathrm{C}.$ What is the apparent percentage of dissociation ? (${\mathrm{K}}_{\mathrm{f}}$ for water $=1.86 \mathrm{K} \mathrm{kg}{ \mathrm{mol}}^{-1}$)

A solution containing $0.011 \mathrm{kg}$ of barium nitrate $\left[\mathrm{Ba}{\left({\mathrm{NO}}_3\right)}_2\right]$ in $0.1 \mathrm{kg}$ of water boils at $100.46°\mathrm{C}$. Calculate the degree of ionization of the salt. ${\mathrm{K}}_{\mathrm{b}}$ (water) $=0.52 \mathrm{K} \mathrm{kg}{ \mathrm{mol}}^{-1}$. $\left[\mathrm{Ba}=137\right]$

A certain mass of a substance, when dissolved in $100 \mathrm{g} {\mathrm{C}}_6{\mathrm{H}}_6$, lowers the freezing point by $1.28°\mathrm{C}$. The same mass of solute dissolved in $100 \mathrm{g}$ water lowers the freezing point by $1.40°\mathrm{C}$. If the substance has normal molecular weight in benzene and is completely ionized in water, into how many ions does it dissociate in water? ${\mathrm{K}}_{\mathrm{f}}$ for ${\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{C}}_6{\mathrm{H}}_6$ are $1.86$ and $5.12 \mathrm{K} \mathrm{kg}{ \mathrm{mol}}^{-1}$.

At $300 \mathrm{K}$, two solutions of glucose in water of concentration $0.01 \mathrm{M}$ and $0.001 \mathrm{M}$ are separated by semipermeable membrane. Pressure needs to be applied on a solution, to prevent osmosis? Calculate the magnitude of this applied pressure in atm?

The vapour pressure of ethanol and methanol are $44.0 \mathrm{mm}$ and $88.0 \mathrm{mm} \mathrm{Hg}$ respectively. An ideal solution is prepared at the same temperature by mixing $69 \mathrm{g}$ of ethanol with $40 \mathrm{g}$ of methanol. Calculate total vapour pressure of the solution.