The swelling in feet and ankles of an aged person due to sitting continuously for long hours during travel, is reduced by soaking the feet in warm salt water. This is because of
A sample of water is found to contain $$5.85 \%$$ $$\left(\frac{w}{w}\right)$$ of $$A B$$ (molecular mass 58.5 ) and $$9.50 \%$$ $$\left(\frac{w}{w}\right) X Y_2$$ (molecular mass 95). Assuming $$80 \%$$ ionisation of $$A B$$ and $$60 \%$$ ionisation of $$X Y_2$$, the freezing point of water sample is [Given, $$K_f$$ for water $$1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$$, Freezing point of pure water is $$273 \mathrm{~K}$$ and $$A, B$$ and $$Y$$ are monovalent ions.]
Match the column A (type of crystalline solid) with the column B (example for each type)
A | B | ||
---|---|---|---|
P. | Molecular solid | i. | SiC |
Q. | Ionic solid | ii. | Mg |
R. | Metallic solid | iii. | H$$_2$$O |
S. | Network solid | iv. | MgO |
A metal crystallises in a body centred cubic lattice with the metallic radius $$\sqrt3\mathop A\limits^o $$. The volume of the unit cell in $$\mathrm{m}^3$$ is