P-block elements practice · Easy

Option A (${XePtF}_6$) is correct because the first noble gas compound prepared by Neil Bartlett in 1962 was Xenon hexafluoroplatinate (${XePtF}_6$).

Option A (Phosphorus) is correct because bone black is a polymorphic form of phosphorus.

Option B (${H_4}{P_2}{O_6}$) is correct because the formula for hypophosphoric acid is ${H_4}{P_2}{O_6}$.

Option C is correct. The percentage of nitrogen in the air is approximately 78% by volume and 75% by weight.

Option C ($Ag$) is correct because nitrogen does not directly combine with silver.

Option D (Bi) is correct because Bismuth (Bi) is known to be brittle and has the least malleability and ductility among the given options.

Option A (${\mathrm{F}_2}$) is correct because UF6 is a gas, allowing for separation of uranium isotopes based on diffusion rates.

Option C (Availability of vacant d-orbital in P but not in N) is correct because phosphorus has vacant d-orbitals that allow it to expand its octet and form five bonds, while nitrogen does not have d-orbitals and cannot exceed four bonds.

Option C is correct because the thermal stability of hydrogen halides decreases down the group due to the decreasing bond dissociation enthalpy. HF is the most stable due to strong hydrogen bonding.

Option B (By heating white phosphorus with aqueous solution of caustic potash) is correct because this is the standard laboratory preparation method for phosphine.

Option D (Free sulphur) is correct because large deposits of sulphur in nature are found in the elemental or free form.

The correct answer is C (Both (1) and (2)) because the reaction of HCl with iron produces H2, which prevents the formation of ferric chloride.

Option A (7) is correct because the acidic oxides listed are N2O3, NO2, SO2, Cl2O7, CrO3, Mn2O7, and P2O3.

Option A is correct because the acidity order of oxyacids of chlorine is $HClO < HClO_2 < HClO_3 < HClO_4$. Therefore, $HClO$ is the weakest acid.