A solution of a substance ‘X’ is used for white washing.

Write the reaction of the substance ‘X’ named in given with water.

When we talk about a substance used for whitewashing, we are typically referring to calcium hydroxide, commonly known as slaked lime. The chemical formula for this substance is Ca(OH)₂. When slaked lime is mixed with water, it undergoes a reaction that produces a milky suspension known as limewater. This is a key component in the whitewashing process, giving surfaces a bright, white finish.

The Reaction of Slaked Lime with Water

The reaction can be represented by the following chemical equation:

CaO (s) + H₂O (l) → Ca(OH)₂ (aq)

In this equation:

• CaO represents calcium oxide, also known as quicklime, which is the precursor to slaked lime.
• H₂O is water.
• Ca(OH)₂ is the resulting slaked lime, which is soluble in water.

The Process Explained

When quicklime (CaO) is added to water, it reacts exothermically, meaning it releases heat. This reaction is quite vigorous and can produce a lot of heat, which is why caution is advised when mixing these substances. The resulting slaked lime is a white powder that can be mixed with water to create a paste suitable for whitewashing.

Why Use Slaked Lime for Whitewashing?

Slaked lime is favored for whitewashing due to several reasons:

• Cost-Effective: It is relatively inexpensive compared to other painting materials.
• Eco-Friendly: Being a natural product, it is less harmful to the environment.
• Antimicrobial Properties: It can help inhibit the growth of mold and bacteria on surfaces.
• Reflective Qualities: The bright white color reflects sunlight, helping to keep buildings cooler.

Application in Whitewashing

To apply slaked lime for whitewashing, the slaked lime is mixed with water to create a thin paste. This paste can then be applied to walls, fences, or other surfaces. As it dries, it forms a hard, durable coating that not only looks good but also protects the underlying material.

In summary, the reaction of slaked lime with water is a fundamental process in creating a mixture that is widely used for whitewashing, providing both aesthetic and protective benefits to various surfaces.