$$ \text { Consider the following three resonance structures } $$

The correct order of their stabilities is
Identify the crystal system in which primitive unit cell has edge lengths $a=b=200 \mathrm{pm}$ and $c=300 \mathrm{pm}$ and all axial angles are same
At 300 K , the osmotic pressure of a decinormal solution of sodium chloride is 4.82 atm . The degree of dissociation of sodium chloride is $x \times 10^{-2}$. The value of $x$ is $\left(R=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$
At 300 K , the conductivity of $0.01 \mathrm{~mol} \mathrm{dm}^{-3}$ aqueous solution of acetic acid is $19.5 \times 10^{-5} \mathrm{mho} \mathrm{cm}^{-1}$ and limiting molar conductivity of acetic acid at the same temperature is $390 \mathrm{mho} \mathrm{cm}^2 \mathrm{~mol}^{-1}$. The degree of dissociation of acetic acid is