P-block elements practice · Easy

Option D (Goitre) is correct because iodine deficiency leads to the enlargement of the thyroid gland, causing goitre.

Option A (Reducing agent) is correct because H2SO4 acts as an oxidizing agent due to sulfur being in its highest oxidation state (+6).

Option A (White P) is correct because white phosphorus is highly reactive and readily reacts with oxygen in the air at ordinary temperatures, often igniting spontaneously.

Option A is correct because ${H_4}{P_2}{O_7}$ (pyrophosphoric acid) has four ionizable hydrogen atoms, making it a tetrabasic acid.

Option B (Fluorspar $-\mathrm{BF}_3$) is incorrectly matched because Fluorspar is $\mathrm{CaF}_2$, not $\mathrm{BF}_3$.

Option B is correct. Assertion and Reason are both true, but the Reason does not explain the Assertion. The dipole moment depends on the vector sum of bond moments and lone pair moments.

Option C (He) is correct because liquid Helium exhibits unique properties like superfluidity and exists in two forms, He(I) and He(II), behaving abnormally compared to other noble gases.

Option D (4) is correct because phosphorus exists as a tetra-atomic molecule, P₄.

Option D ($N{H_3}$) is correct because bacteria convert molecular nitrogen into ammonia ($N{H_3}$) through the process of nitrogen fixation.

Option B ($\mathrm{N}{\mathrm{H}_4}\mathrm{N}{\mathrm{O}_3}$) is correct because TNT mixed with ammonium nitrate forms an explosive material used for blasting.

Option B ($N{H_4}N{O_3}$) is correct because Ammonium nitrate is mixed with TNT to make it a more powerful and safer explosive.

Option A (Dithionous acid) is correct because the oxidation state of sulfur in dithionous acid (H₂S₂O₄) is +3.

Option C (Smell of ammonia) is correct because heating ammonium chloride with NaOH produces ammonia gas, which has a characteristic pungent smell.

Option A (Is monoatomic) is correct because noble gases are monoatomic, meaning they consist of single atoms, and therefore do not have vibrational modes.

Option B ($C{l_2}$) is correct because chlorine is used in the preparation of many insecticides, such as DDT.

Option B (${NaClO}_3$) is correct because chlorine reacts with hot and concentrated NaOH to produce sodium chlorate (${NaClO}_3$), sodium chloride (NaCl), and water.

Option A ($n s^2 n p^5$) is correct because group 17 elements (halogens) have 7 valence electrons, which corresponds to the electronic configuration $n s^2 n p^5$.

Option D ($2HN{O_3} + {P_2}{O_5} \to \mathrm{ }2HP{O_3} + {N_2}{O_5}$) is correct because in this reaction, $HNO_3$ acts as a dehydrating agent rather than an oxidizing agent.

Option B (Turpentine oil) is correct as it is a known fact that ozone readily dissolves in turpentine oil.

Option A (Oxygen) is correct because the oxygen molecule (O2) has two unpaired electrons, making it paramagnetic.

Option A (Sodium metal is stored under kerosene) is correct because sodium reacts vigorously with air and water, so it's stored in kerosene to prevent this.

Option C is correct because it is necessary to use a silent electrical discharge in the preparation of ozone to prevent its decomposition, and the formation of ozone from oxygen is an endothermic process, not exothermic.

Option B ($NaCl{O_3}$) is correct because chlorine reacts with hot concentrated NaOH to form sodium chlorate ($NaCl{O_3}$) along with sodium chloride and water.

Option C (Siemens and Halske’s ozonizer) is correct because ozone is manufactured using Siemens and Halske's ozonizer by carrying out a silent electric discharge.

Option D (None of these) is correct because $NF_3$ does not undergo hydrolysis at room temperature due to the absence of vacant d-orbitals on nitrogen and the high electronegativity of fluorine.

Option D (Hardly affects $\mathrm{Al}$) is correct because aluminum forms a passive layer of aluminum oxide ($\mathrm{A}{\mathrm{l}_2}{\mathrm{O}_3}$) on its surface when exposed to nitric acid, preventing further reaction.

Option C (Fluorine) is correct because Xenon directly combines with Fluorine to form fluorides.

Option D (All of these) is correct because all the given expressions are valid representations of Kf, the cryoscopic constant.

Option C (Sulphur) is correct because sulphur exhibits allotropy, existing in different forms such as rhombic, monoclinic, and plastic sulphur.

Option A is correct because NaOH is a base and can absorb acidic oxides like N2O5, forming a salt and water.