Identify the correct statements from the following :

A. Heisenberg uncertainty principle is applicable to electrons.

B. The size of $2 p_x$ orbital is less than the size of $3 p_x$ orbital.

C. The energy of 2 s orbital of H atom is equal to the energy of 2 s orbital of Li .

D. The electronic configuration of Cr is $[\mathrm{Ar}] 3 \mathrm{~d}^5 4 \mathrm{~s}^1$

Choose the correct answer from the options given below:

What is the mole fraction of water in $10 \%$ by weight $(\mathrm{w} / \mathrm{w})$ of aqueous urea solution?

[Given: Molar mass of $\mathrm{H}, \mathrm{O}, \mathrm{C}$ and N are $1,16,12$ and $14 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively.]

$\mathrm{M}_3 \mathrm{~A}_2$ is a sparingly soluble salt of molar mass $y \mathrm{~g} \mathrm{~mol}^{-1}$ and solubility $x \mathrm{~g} \mathrm{~L}^{-1}$. The ratio of the molar concentration of the anion $\left(\mathrm{A}^{3-}\right)$ to the solubility product of the salt is

Arrange the following resultant mixtures in increasing order of their pH values

A. $10 \mathrm{~mL} 0.2 \mathrm{M} \mathrm{Ca}(\mathrm{OH})_2+25 \mathrm{~mL} 0.1 \mathrm{M} \mathrm{HCl}$

B. $10 \mathrm{~mL} 0.01 \mathrm{M} \mathrm{H}_2 \mathrm{SO}_4+10 \mathrm{~mL} 0.01 \mathrm{M} \mathrm{Ca}(\mathrm{OH})_2$

C. $10 \mathrm{~mL} 0.1 \mathrm{M} \mathrm{H}_2 \mathrm{SO}_4+10 \mathrm{~mL} 0.1 \mathrm{M} \mathrm{KOH}$

Choose the correct answer from the options given below :