Animated Solution for Chemistry - s and p-Block Elements: Match List-I with List-II. $\begin{array}{ll}\text{List-I (Industrial process)}& \text{List-II (Application)}\\ \text{A. Haber’s process}& \text{(i) }{\text{HNO}}_3\text{ synthesis}\\ \text{B. Ostwald’s process}& \text{(ii) Aluminium extraction}\\ \text{C. Contact process}& \text{(iii) }{\text{NH}}_3\text{ synthesis}\\ \text{D. Hall-Heroult process}& \text{(iv) }{\text{H}}_2{\text{SO}}_4\text{ synthesis}\end{array}$ Choose the correct answer from the options given below :

Welcome to a fascinating journey through the backbone of modern civilization: Industrial Chemistry. The question before us is a classic matching problem that tests our knowledge of the most pivotal chemical processes ever developed. These aren't just equations in a textbook; these are the very reactions that feed the world, build our cities, and power our industries. Let's break down each of these legendary processes and understand the magic behind them.

Feeding the World

Imagine a world where we couldn't grow enough food to sustain the population. That was a very real fear in the early 20th century until Fritz Haber and Carl Bosch came along. Haber's process is the industrial method for synthesizing ammonia (${\text{NH}}_3$).

It takes the incredibly stubborn and unreactive nitrogen gas (${\text{N}}_2$) from the atmosphere and forces it to react with hydrogen gas (${\text{H}}_2$) under high pressure and moderate temperature, using an iron catalyst.

This ammonia is the primary ingredient in synthetic fertilizers, which are responsible for sustaining nearly half of the global population today. Therefore, A matches with (iii).

The Power of Nitric Acid

Once we have ammonia from Haber's process, what else can we do with it? Enter Wilhelm Ostwald. Ostwald's process is the method used to manufacture nitric acid (${\text{HNO}}_3$).

This is a multi-step process. First, ammonia is catalytically oxidized using a platinum-rhodium gauge to form nitric oxide ($\text{NO}$).

This nitric oxide is further oxidized to nitrogen dioxide (${\text{NO}}_2$), which is then absorbed in water in the presence of oxygen to yield nitric acid.

Nitric acid is crucial for making fertilizers (like ammonium nitrate) and explosives (like TNT). Thus, B matches with (i).

The King of Chemicals

If there is one chemical whose production volume dictates the industrial health of a nation, it is sulfuric acid (${\text{H}}_2{\text{SO}}_4$). The Contact process is the modern method for producing this "king of chemicals".

The critical step here is the catalytic oxidation of sulfur dioxide (${\text{SO}}_2$) to sulfur trioxide (${\text{SO}}_3$) using a vanadium pentoxide (${\text{V}}_2{\text{O}}_5$) catalyst.

Instead of dissolving ${\text{SO}}_3$ directly in water (which creates a dangerous, highly exothermic acid mist), it is absorbed into existing concentrated sulfuric acid to form oleum (${\text{H}}_2{\text{S}}_2{\text{O}}_7$), which is then safely diluted with water to produce more sulfuric acid. Therefore, C matches with (iv).

The Age of Aluminium

Before the late 19th century, aluminium was considered a precious metal, more valuable than gold, because it was so incredibly difficult to extract from its ore. The Hall-Heroult process changed everything.

This process involves the electrolytic reduction of alumina (${\text{Al}}_2{\text{O}}_3$) dissolved in molten cryolite (${\text{Na}}_3{\text{AlF}}_6$). The cryolite lowers the melting point of the mixture drastically and improves electrical conductivity. Carbon electrodes are used, and the oxygen liberated at the anode reacts with the carbon to form carbon dioxide.

This process made aluminium cheap and abundant, leading to its use in everything from soda cans to airplanes. Thus, D matches with (ii).

By carefully analyzing each industrial process, we have successfully mapped them to their respective applications: - A $\to$ (iii) - B $\to$ (i) - C $\to$ (iv) - D $\to$ (ii)

Looking at our given options, this sequence perfectly aligns with option (c). Mastering these processes is not just about scoring marks; it's about appreciating the chemical engineering marvels that shape our modern world!