P-block elements practice · Mixed difficulty

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.

The correct answer is A (A liquid oxidizer and a solid fuel) because hybrid rocket propellants typically use a liquid oxidizer and a solid fuel for combustion.

Option A (If both Assertion & Reason are True & the Reason is correct explanation of the Assertion) is correct because $\mathrm{O}_2\mathrm{F}_2$ is indeed used for Plutonium purification by converting it to $\mathrm{PuF}_6$, which is volatile.

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 D is correct. HI is a strong reducing agent and reduces HNO3 to NO2, while HI itself gets oxidized to I2.

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.