Animated Solution for Chemistry - s and p-Block Elements: Match the following compounds (Column -I) with their uses (Columns -II). $\begin{array}{ll}\text{Column -I}& \text{Column - II}\\ \text{(I) }{\text{Ca(OH)}}_2& \text{(A) Casts of statues}\\ \text{(II) }\text{NaCl}& \text{(B) White wash}\\ \text{(III) }{\text{CaSO}}_4\cdot \frac{1}{2}{\text{H}}_2\text{O}& \text{(C) Antacid}\\ \text{(IV) }{\text{CaCO}}_3& \text{(D) Washing soda preparation}\end{array}$

The s-block elements and their compounds are not just abstract chemicals in a textbook; they are deeply woven into our everyday lives. This question is a beautiful reminder of how chemistry operates all around us, from the walls of our houses to the medicines we take. Let's break down the uses of each of these fascinating compounds.

First on our list is calcium hydroxide, ${\text{Ca(OH)}}_2$, commonly known as slaked lime. If you've ever seen a house being painted with a traditional white wash, you've seen this compound in action.

When slaked lime is applied to walls, it doesn't just dry; it undergoes a slow chemical reaction. It absorbs carbon dioxide (${\text{CO}}_2$) from the air to form a thin, hard, and shiny layer of calcium carbonate (${\text{CaCO}}_3$). This is what gives white-washed walls their characteristic bright finish. Therefore, ${\text{Ca(OH)}}_2$ perfectly matches with white wash.

Next, we have sodium chloride, $\text{NaCl}$. While we all know it as table salt, its industrial importance is massive. It is a primary raw material in the Solvay process, which is used to manufacture washing soda (${\text{Na}}_2{\text{CO}}_3$).

In the Solvay process, ammonia, water, and carbon dioxide react to form ammonium bicarbonate. This intermediate then reacts with our $\text{NaCl}$ to precipitate sodium bicarbonate (${\text{NaHCO}}_3$). Finally, heating this sodium bicarbonate yields the desired washing soda.

Thus, $\text{NaCl}$ is intrinsically linked to washing soda preparation.

Moving on to calcium sulphate hemihydrate, ${\text{CaSO}}_4\cdot \frac{1}{2}{\text{H}}_2\text{O}$. This compound is universally famous as Plaster of Paris (POP).

The magic of POP lies in its hydration. When mixed with an appropriate amount of water, it rapidly sets into a hard, solid mass known as gypsum (${\text{CaSO}}_4\cdot 2{\text{H}}_2\text{O}$). Because it forms a workable paste before hardening, it is the perfect material for molding. It is extensively used for making casts of statues, decorative ceilings, and even for immobilizing fractured bones in orthopedics.

Finally, we look at calcium carbonate, ${\text{CaCO}}_3$. This naturally occurring mineral (found in limestone and marble) is mildly basic.

When you suffer from indigestion or acidity, your stomach has overproduced hydrochloric acid ($\text{HCl}$). Calcium carbonate acts as an effective antacid. It reacts with the excess stomach acid, neutralizing it and releasing carbon dioxide gas, which provides quick relief.

Hence, ${\text{CaCO}}_3$ is a classic antacid.

By connecting the dots: ${\text{Ca(OH)}}_2$ $\to$ White wash $\text{NaCl}$ $\to$ Washing soda preparation ${\text{CaSO}}_4\cdot \frac{1}{2}{\text{H}}_2\text{O}$ $\to$ Casts of statues ${\text{CaCO}}_3$ $\to$ Antacid

This sequence perfectly matches option (b). Chemistry is truly everywhere!