- ✓

- B

- C

- D






Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Assertion $(A):$ The ionic radii of $O ^{2-}$ and $Mg ^{2+}$ are same.
Reason $( R )$ : Both $O ^{2-}$ and $Mg ^{2+}$ are isoelectronic species.
In the light of the above statements, choose the correct answer from the options given below
Assertion $(A) :$ At $10^{\circ} C$, the density of a $5\, M$ solution of $KCl$ [atomic masses of $K$ and $Cl$ are $39$ and $35.5\, g \,mol ^{-1}$ ]. The solution is cooled to $-21^{\circ} C$. The molality of the solution will remain unchanged.
Reason $(R):$ The molality of a solution does not change with temperature as mass remains unaffected with temperature.
In the light of the above statements, choose the correct answer from the options given below
(Nearest integer)
[Atomic weight : $\mathrm{H}=1.008 ; \mathrm{C}=12.00 ; \mathrm{O}=16.00$ ]