Direction for the question 46 to 50:  Question is based on following passage:
p-block elements are placed in groups 13 to 18 of the periodic table. Group 15 is nitrogen family. Nitrogen makes various compounds like NH3, HNO3, N2O, NO2 etc. Phosphorus exists in the form of white and red phosphorus. White phosphorus glows in dark. PH3 gas is used as smoke screen. Group 16 is called oxygen family. Dry air contains 21% O2 gas by volume. Combined sulphur exists as sulphates such as gypsum, epsome salt, baryte etc. The allotropic forms of sulphur are Rhombic and monoclinic sulphur. S2 is paramagnetic like O2 and it stable at high temperature. Group 17 is Halogen family. F2 is highly reactive, Cl2 is greenish yellow gas. Both SO2 and Cl2 are used for bleaching. Group 18 is Noble gas family but some noble gases also form compounds. Complete hydrolysis of XeF6 gives HF and XeO3 as main products.

Question: Match List-I with List-II:

List-I	List-II
$\left(A\right)\text{Ammonia}$	$\left(I\right)\text{Rotten fish smell}$
$\left(B\right)\text{Nitric Acid}$	$\left(\mathrm{II}\right)\text{Detection of metal ions}$
$\left(C\right)\text{Phosphene}$	$\left(\mathrm{III}\right)\text{Chemiluminescence}$
$\left(D\right)\text{White Phosphorus}$	$\left(\mathrm{IV}\right)\text{Ostwald Process}$

Choose the correct answer from the options given below:

The correct answer is (A)-(II), (B)-(IV), (C)-(I), (D)-(III).

To understand why this is the correct match, let us examine each item in List-I and find its corresponding description or application in List-II:

(A) Ammonia matches with (II) Detection of metal ions:
Ammonia aqueous solution (${\text{NH}}_3·{\text{H}}_2\text{O}$ or ${\text{NH}}^{4+}+{\text{OH}}^{-}$) is a weak base and acts as a Lewis base due to the presence of a lone pair of electrons on the nitrogen atom. It forms complex compounds with various transition metal ions, which is useful in their qualitative detection and separation. For example, when ammonia is added to a solution containing copper ions (${\text{Cu}}^{2+}$), it forms a characteristic deep blue tetraamminecopper(II) complex:
$${\text{Cu}}^{2+}\left(\text{aq}\right)+4{\text{NH}}_3\left(\text{aq}\right)\Rightarrow {\left[\text{Cu}\right({\text{NH}}_3{)}_4]}^{2+}\left(\text{aq}\right)\left(\text{Deep Blue}\right)$$
Similarly, silver ions (${\text{Ag}}^{+}$) form a soluble diamminesilver(I) complex, which helps in identifying silver halides.

(B) Nitric Acid matches with (IV) Ostwald Process:
Nitric acid (${\text{HNO}}_3$) is manufactured on a large scale by the Ostwald process. In this process, ammonia is catalytically oxidized by atmospheric oxygen in the presence of a platinum/rhodium gauge catalyst at high temperatures and pressures to form nitric oxide ($\text{NO}$), which is subsequently converted into nitrogen dioxide (${\text{NO}}_2$) and then absorbed in water to yield nitric acid.

(C) Phosphine (spelled Phosphene in the table) matches with (I) Rotten fish smell:
Phosphine (${\text{PH}}_3$) is a highly toxic, colorless gas. It has a very characteristic and unpleasant odor resembling rotten fish or decaying garlic, which makes it easily identifiable even at low concentrations.

(D) White Phosphorus matches with (III) Chemiluminescence:
White phosphorus (${\text{P}}_4$) is highly reactive and undergoes slow oxidation when exposed to air in the dark, emitting a faint greenish-yellow glow. This phenomenon of emitting light as a result of a chemical reaction without generating significant heat is known as chemiluminescence (often referred to as phosphorescence in common terms, though chemically it is chemiluminescence).

Therefore, combining all these correct associations:
(A) Ammonia → (II) Detection of metal ions
(B) Nitric Acid → (IV) Ostwald Process
(C) Phosphine → (I) Rotten fish smell
(D) White Phosphorus → (III) Chemiluminescence