Chromic acid, with the chemical formula H₂CrO₄, is a potent oxidizing agent known for its strong acidity and reactivity. It is an unstable compound that readily reacts with itself to form dichromate acid (H₂Cr₂O₇). This compound is also highly hygroscopic, absorbing moisture from the air.

Key Properties
Chemical Formula: H₂CrO₄

Molecular Weight: 118.0 g/mol

Appearance: Dark purplish-red crystalline solid or powder

Melting Point: 197°C (386.6°F)

Density: 1.201 g/cm³

Solubility: Highly soluble in water, acetic acid, pyridine, and ether

Synthesis and Purification
Chromic acid is typically formed by dissolving chromium trioxide (CrO₃) in water or by adding concentrated sulfuric acid to a dichromate solution. The crude CrO₃ is precipitated from a mixture of saturated sulfuric acid and saturated sodium bichromate. The precipitate is then purified by crystallization or melting.

Applications
Oxidizing Agent: Utilized in organic synthesis for the oxidation of primary alcohols to aldehydes and secondary alcohols to ketones.

Chromium Plating: Essential in the chrome plating industry, providing a durable and aesthetically pleasing finish to metal surfaces.

Ceramics and Glass: Used in the production of ceramic glazes and colored glass, imparting vibrant colors.

Cleaning and Etching: Employed in laboratories for cleaning glassware and etching materials due to its strong oxidative properties.