The key difference between acid and acidic is that the term acid describes the chemical compounds that can ionize in water to release hydrogen ions whereas the term acidic refers to the ability to release hydrogen ions.
Acids are substances having a pH value of less than 7 and they react with metals and bases. Also, one characteristic of acids is that they taste sour. However, the term acidic is an adjective that we use to describe the properties of a substance that has similar properties to an acid.
CONTENTS
1. Overview and Key Difference
2. What is Acid
3. What is Acidic
4. Side by Side Comparison – Acid vs Acidic in Tabular Form
5. Summary
What is Acid?
Acid is a chemical compound that can release hydrogen ions in water. Furthermore, acids have a pH value less than 7, and they also have a sour taste. Also, there are three major categories of acids. Namely, they are strong acids, moderately strong acids and weak acids. Strong acid completely ionizes to release all possible hydrogen ions to the aqueous solution whereas weak acid partially ionizes.
Furthermore, there are two broad categories of acids. Namely, they are Brønsted and Lewis acids. Brønsted acids are the proton donors. In aqueous solutions, they can form hydronium ions (H3O+) by donating a proton (H+) to the water molecule (H2O). Lewis acids are chemical compounds which can form a covalent bond with an electron pair.
Figure 01: Reaction between HCl Acid and NH4OH Base
We can measure the acid strength of acid from the acid dissociation constant or Ka. This gives how much an acid dissociates into its ions. For the dissociation of HA acid into H+ and A– ions, we can write an equation to determine the Ka value as follows:
Ka = [H+][A–] / [HA]
A base can neutralize an acid. The reaction between an acid and a base gives salt and water. For instance, the reaction between HCl acid and NaOH base gives NaCl salt and a water molecule.
What is Acidic?
The term acidic is useful in describing the properties of a substance that has similar properties to an acid. Or else, we can use it to express the presence of an acid. Sometimes, we use this term to give an idea about the pH of a solution as pH<7 (pH is below 7).
Figure 02: pH Scale for Acidic and Alkaline Substances
For example, food items are termed as alkaline or acidic depending upon their ability to produce basic or acidic ash inside the stomach after their digestion. It is why we classify foods as alkaline or acidic, and doctors advise us to include more and more of alkaline foods in our diet. When we eat foods, they oxidize inside the body, and after digestion, they leave a residue or ash. If this residue contains minerals such as sulfur, phosphorus, chlorine, and organic acid radicals more than sodium, potassium, calcium and magnesium, the foods are termed awe categorize the food as acidic. In contrast, the converse of this phenomenon is also true, and the foods are then termed as alkaline.
What is the Difference Between Acid and Acidic?
An acid is a chemical compound that can release hydrogen ions in water whereas the term acidic is useful in describing the properties of a substance that has similar properties to an acid. Therefore, this is the key difference between acid and acidic. In brief, the term acid is useful in naming a chemical compound while the term acidic is useful to explain the presence of properties of an acid.
Summary – Acid vs Acidic
The term acidic derives from the name acid. The key difference between acid and acidic is that the term acid describes the chemical compounds that can ionize in water to release hydrogen ions whereas the term acidic refers to the ability to release hydrogen ions.
Reference:
1. “Acid.” Wikipedia, Wikimedia Foundation, 30 Oct. 2018. Available here
2. “Acidic | Definition of Acidic in English by Oxford Dictionaries.” Oxford Dictionaries | English, Oxford Dictionaries. Available here
Image Courtesy:
1.”Hydrochloric acid ammonia” (Public Domain) via Commons Wikimedia
2.”35805740223″ by Heinrich-Böll-Stiftung (CC BY-SA 2.0) via Flickr