The key difference between Caro’s acid and Marshall’s acid is that Caro’s acid contains one sulfate group, whereas Marshall’s acid contains two sulfate groups.
Caro’s acid and Marshall’s acid are inorganic acid compounds containing sulfate groups. They are named as peroxymonosulfuric acid and peroxydisulfuric acid, respectively. As these names imply, these inorganic compounds contain peroxide groups and sulfate groups together; the sulfate groups in the peroxydisulfuric acid are connected through a peroxide group.
CONTENTS
1. Overview and Key Difference
2. What is Caro’s Acid
3. What is Marshall’s Acid
4. Side by Side Comparison – Caro’s Acid vs Marshall’s Acid in Tabular Form
5. Summary
What is Caro’s Acid?
Caro’s acid is an inorganic acid containing a sulfate group and a peroxide group. We can name it as peroxymonosulfate acid because it contains one peroxide group and one sulfate group. The chemical formula of this compound is H2SO5. In this compound, the sulfur atom is in the centre and it has a tetrahedral geometry. We can indicate the connectivity of the atoms as HO-O-S(O2)-OH.
Caro’s acid is a strong oxidant and it is highly explosive as well. The scientist Heinrich Caro, 1898 found this acid, so it was named after him. When considering the production of this acid, in a laboratory procedure, we need chlorosulfuric acid and hydrogen peroxide. When produced, it appears as white crystals. The molar mass of the compound is 114 g/mol.
In the aspect of usage, this acid is used in cleaning and disinfection. For example, the treatment of water in swimming pool to get rid of contaminants. Moreover, the ammonium salt of this acid is useful in plastic industry, as polymerization initiators. It is also important as an oxidizing agent.
What is Marshall’s Acid?
Marshall’s acid is an inorganic acid containing two sulfate groups and a peroxide group. The chemical formula of this compound is H2S2O8. It got its name from the chemist Hugh Marshall, who found this compound. We can name this compound as peroxydisulfuric acid because of the presence of two sulfate groups. Moreover, we can write the structural formula of this compound as HO3S-O-O-SO3H.
We can prepare this compound using the reaction between chlorosulfuric acid hydrogen peroxide. We can also produce it via electrolysis of sulfuric acid (concentrated acid) using platinum electrodes. Here, we need to use a high voltage as well. When considering the uses of Marshall’s acid, it is mainly useful as a powerful oxidizing agent.
What is the Difference Between Caro’s Acid and Marshall’s Acid?
Caro’s acid and Marshall’s acid are important inorganic acids containing sulfate groups. The key difference between Caro’s acid and Marshall’s acid is that Caro’s acid contains one sulfate group, whereas Marshall’s acid contains two sulfate groups. The chemical name of Caro’s acid is peroxysulfuric acid, while the chemical name of Marshall’s acid is peroxydisulfuric acid.
Moreover, both these compounds are important as powerful oxidizing agents. But, in addition to it, Caro’s acid is also useful as a cleaning agent and for disinfection purposes. Besides, we can write the structural formula of Caro’s acid as HO-O-S(O2)-OH, and the structural formula of Marshall’s acid is HO3S-O-O-SO3H.
Below infographic summarizes the differences between Caro’s acid and Marshall’s acid.
Summary – Caro’s Acid vs Marshall’s Acid
Caro’s acid and Marshall’s acid are important inorganic acids containing sulfate groups. The key difference between Caro’s acid and Marshall’s acid is that Caro’s acid contains one sulfate group, whereas Marshall’s acid contains two sulfate groups.
Reference:
1. “Peroxymonosulfuric Acid.” Wikipedia, Wikimedia Foundation, 28 Aug. 2019, Available here.
2. “H2S2O8 – Peroxydisulfuric Acid Structure, Molecular Mass, Properties and Uses.” BYJUS, Byjus, 2 May 2019, Available here.
Image Courtesy:
1. “Peroxomonoschwefelsäure” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia
2. “Peroxodischwefelsäure” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia