Chromic Acid: Overview, Questions, Preparation

This chapter has multiple topics listed below:

Acids, Bases and Salts Acid Strength Difference between Acid and Bas...Examples of Bases Zinc carbonate Zinc Nitrate Aluminium Phosphate Aspartic Acid Butyric Acid Tannic acid Uses of Folic Acid Uses of Acetic Acid Lactic Acid formula Uses of Citric Acid Magnesium Nitrate Barium Iodide Dilute Acids Magnesium Phosphate Uses of Hydrochloric Acid List of Strong Acids Butanoic Acid Sodium Chlorate Barium Carbonate Chloroacetic Acid Magnesium Bicarbonate Red Cabbage Indicator Sodium Hexametaphosphate Zinc Hydroxide Potassium Iodate Peroxydisulfuric Acid Ph of Acids and Bases Potassium Bromate Weak Acid Examples Weak Bases Magnesium Hydroxide Monosodium Glutamate Potassium Hydroxide Nitrous Acid Henderson Hasselbalch Equation Difference between Alkali and B...Properties of Bases Sodium Citrate Ammonium Phosphate Chemical Indicators Chromic Acid Perchloric Acid Uses of Sodium Hydroxide Zinc Acetate

Yamini Saini

Updated on Jun 30, 2021 09:30 IST

Chromic acid is widely known as Tetraoxochromic acid or Chromic(VI) acid. Typically, it is a blend created by applying a dichromate composed of several compounds and strong chromium trioxide to condensed sulphuric acid (H2SO4).

Molecular Chromic Acid

H2CrO4 is equivalent to sulfuric acid and both are heavy acids, but only the first proton is readily lost.

Dichromic Acid

The completely protonated form of the dichromate ion is H2Cr2O7. It is also seen as the result of the molecular chromic acid addition of chromium trioxide.

Table of Contents

Chromic Acid Properties
Applications of Chromic acid
Illustrated Examples
FAQs on Chromic Acid

Chromic Acid Properties

Chromic Acid	H2CrO4
Molecular Weight	118.008 g/mol
Density	1.201 g/cm3
Melting Point	197 C
Boiling Point	250 C

Applications of Chromic acid

Chromic acid behaves in the plating of chromium as an intermediate
It is detected in ceramic and coloured glass glazes
A good oxidising agent that is used to disinfect laboratory glassware is Chromosulfuric acid or Sulfochromic mixture
It is capable of brightening raw brass and is thus put to use in the field of instrument repair
It was used in hair dye in the year 1940

Dichromic acid is the completely protonated structure of the dichromate ion, which can also be used as the result of CrO3 being added to molecular chromic acid. Dichromic acid may behave the alike way when reacting with an aldehyde or a ketone. The alert to this claim, however, is that a secondary ketone will be oxidised by no more than a ketone and dichromic acid will only oxidize the aldehyde.

Safety Hazards

Chromic acids are potent oxidizers, and if combined with any readily oxidizable organic compounds that can cause explosions or fires, they can react violently. In the case of any burn caused by this acid, a dilute solution of sodium thiosulfate is used to treat it.

Chromic acid in Class 10

This concept is taught in the chapter Acids, Bases and Salts. You will be taught about its structure, mechanism and its reaction with compounds. The weightage is 3 marks.

Illustrated Examples

Which alcohol can not be oxidized by chromic acid?

Primary alcohols are oxidized into carboxylic acids by chromic acid and secondary alcohols are oxidised into ketones. Tertiary alcohols, under moderate conditions, do not react with chromic acid.

Is chromic acid a strong acid?

When chromium trioxide reacts with water, chromic acid is formed. Chromium trioxide is crystalline in colour, light red or brown, and is water-delicate and fully soluble. Chromic acid is a very weak acid and even acetic acid can be dissociated from its salts.

What's the chromic acid colour?

Test with Chromic Acid. In acetone, H2CrO4 chromic acid is a dark red-orange colour. Because of the formation of the Cr3+ ion, compounds that are easily oxidised cause the solution to turn green.

FAQs on Chromic Acid

Q. What use does chromic acid have?

A. As an intermediate in chromium plating, this compound is commonly used. In coloured glass and ceramic glazes, Chromic Acid is also used. This compound was an integral component of many hair dyes in the 1940s.

Q. How do we prepare chromic acid?

A. Chromic acid is formed by applying sulphuric acid to the paste and mixing continuously. Next, in order to make a paste, sodium dichromate or potassium dichromate must be mixed with a little water.

Q. What neutralising agents are suitable for chromic acid neutralisation?

A. Sodium/potassium metabisulfite, sodium thiosulfate, or sodium sulfite are some excellent neutralising agents.

Q. What does chromic acid react with?

A. Alcohols are oxidised by chromic acid in aqueous sodium dichromate solutions. To form a chromic ester in which the alcohol atom of oxygen bridges the atoms of carbon and chromium, it reacts with alcohols.

Q. Is chromic acid poisonous?

A. Hexavalent chromium derivatives are poisonous and carcinogenic (including CrO 3 , chromic acids, chromates, chlorochromatium). This is why, except for the aerospace industry, chromic acid oxidation is not seen on a commercial scale.