Difference Between Organic Acid and Inorganic Acid

Organic Acid vs Inorganic Acid

Acids are defined in several ways by various scientists. Arrhenius defines an acid as a substance that donates H3O+ ions in the solution. Bronsted- Lowry defines an acid as a substance that can donate a proton. Lewis acid definition is far common than the above two. According to it, any electron pair acceptor is an acid. According to the Arrhenius or Bronsted-Lowry definition, a compound should have a hydrogen and the ability to donate it as a proton to be an acid. But according to Lewis, there can be molecules, which don’t possess hydrogen, but can act as an acid. For example, BCl3 is a Lewis acid, because it can accept an electron pair. An alcohol can be a Bronsted-Lowry acid, because it can donate a proton, however according to Lewis, it will be a base.

Regardless of the above definitions, we normally identify an acid as a proton donor. Acids have a sour taste. Lime juice, vinegar are two acids we come across at our homes. They react with bases producing water, and also they react with metals to form H2, thus increase metal corrosion rate. Acids can be categorized into two, based on their ability to dissociate and produce protons. Strong acids are completely ionized in a solution to give protons. Weak acids are partially dissociates and give fewer amounts of protons. Ka is the acid dissociation constant. It gives an indication of the ability to lose a proton of a weak acid. To check whether a substance is an acid or not we can use several indicators like litmus paper or pH paper. In the pH scale from 1-6 acids are represented. An acid with pH 1 is said to be very strong and as the pH value increases, acidity is decreased. Moreover, acids turn blue litmus to red. All the acids can be divided into two as organic acids and inorganic acids depending on their structure.

Organic Acid

These are organic compounds, which can act as acids. Organic acids essentially contain hydrogen and carbon with another element/s. Most common organic acids are acetic acid, lactic acid, citric acid, formic acid, etc. These acids have a –COOH group. Sometimes organic compounds having –OH, -SH groups can act as acids too. For example, alcohols have acidic properties. Acetylene can also donate a proton showing acidic properties. The hydrogens attach to alpha carbon of the aldehydes, and ketones are also acidic protons. Often, organic acids are weak acids and partially dissociate in water.

Inorganic Acid

These are also known as mineral acids, and they are derived from mineral sources. Inorganic acids release protons when dissolved in water. There can be strong inorganic acids like HCl, HNO3, H2SO4 and weak inorganic acids like HCN or H2S.

What is the difference between Organic and Inorganic Acids?

¤ Organic acids contain carbon, and inorganic acids don’t contain carbon.

¤ Generally organic acids are weaker acids than inorganic acids.

¤ Most of the organic acids are insoluble in water (sometimes miscible with water), but soluble in organic solvents. But inorganic acids are generally well soluble in water and non soluble in organic solvents.

¤ Organic acids have a biological origin, whereas inorganic acids haven’t. Inorganic acids are derived from inorganic compounds/mineral sources.

¤ Mineral acids are highly reactive with metals, and they have corrosive ability than the organic acids.

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