The $pH$ of a $0.1 \ M$ monobasic acid solution is $2$. Its osmotic pressure at $T$ Kelvin temperature is ............. $RT$.

$1 \, \text{mole}$ of each of $A$ and $B$ form an ideal solution of vapour pressure $100 \, \text{mm Hg}$. Addition of $2 \, \text{moles}$ of $B$ to it decreases the vapour pressure by $20 \, \text{mm Hg}$. The vapour pressure of $A$ and $B$ in pure state are,respectively:

Evaluate the following statements for their correctness.
$(A)$ The elevation in boiling point temperature of water will be same for $0.1 \ M \ NaCl$ and $0.1 \ M$ urea.
$(B)$ Azeotropic mixtures boil without change in their composition.
$(C)$ Osmosis always takes place from hypertonic to hypotonic solution.
$(D)$ The density of $32 \% \ H_2SO_4$ solution having molarity $4.09 \ M$ is approximately $1.26 \ g \ mL^{-1}$.
$(E)$ $A$ negatively charged sol is obtained when $KI$ solution is added to silver nitrate solution.
Choose the correct answer from the options given below:

$100 \ g$ each of two solutions,one containing $20 \%$ by mass of $NaOH$ and the other $40 \%$ by mass of $NaOH$,are mixed. The density of the resulting solution is $1.25 \ g/mL$. Find the new $\% \ w/v$ of $NaOH$ in the final solution.

An aqueous solution of urea (molar mass $60 \ g \ mol^{-1}$) boils at $100.18 \ ^\circ C$ at $1 \ atm$ pressure. If $K_f$ and $K_b$ for water are $1.86$ and $0.512 \ K \ kg \ mol^{-1}$ respectively,at what temperature will this solution freeze (in $K$)?

The values of $K_b$ and $K_f$ for water are $0.52 \, K \, kg \, mol^{-1}$ and $1.86 \, K \, kg \, mol^{-1}$ respectively. If the solution boils at $0.78 \, K$ above the boiling point of water,then the freezing point of the solution will be ........ $K$.