An acid is any chemical(generally hydrogen-containing) that is capable of donating a proton (hydrogen ion) to another chemical. They are naturally occurring substances which we use in our day-to-day life such as vinegar (acetic acid), citric acid(in citrus fruits), boric acid (for washing). Many of the acids, which we do not consume in the household are used in the laboratories and industries such as hydrochloric acid, hydrofluoric acid, sulfuric acid, etc. In this article, we discuss the physical and chemical properties of acids.
Theories of acids
There are three different theories to define acids based on their properties. You can read our blog post on “10 types of acids” for a detailed explanation.
- Arrhenius’s theory of acids – States that an acid generates hydrogen ions in a solution.
- Bronsted-Lowey theory – It states an acid as a proton donor
- Lewis Theory of acids – which describes that “acids as electron-pair acceptors
Properties of Acids
Physical properties of acids
- Acids are sour in taste. (Warning: Do not taste any chemical). The sour taste of most citric fruits is due to the presence of citric acid.
- Acids have the ability to conduct electricity. Aqueous acidic solutions are used as strong electrolytes.
- Acids are corrosive in nature. Should be handled with care otherwise, they can corrode our skin
- Acids are mostly present in liquid or gaseous forms. But we do have solid acids like zeolitic materials.
- Acidic fumes will burn your nose (Warning: Never inhale acidic fumes)
- Acids would turn litmus paper red
- Acids are colorless with the addition of phenolphthalein
- Acids turn red with the addition of methyl orange
- Acids are identified by shades of red and yellow color with universal indicator solution.
- Most acids can be diluted with water to reduce the intensity of their acidity.
Chemical properties of acids
- Acids have a pH of less than 7.
- Acids have the ability to furnish hydronium ions in aqueous solutions.
- Acids react with active metals to yield hydrogen gas.
- Acids react with a base to produce a salt compound and water. When equal moles of an acid and base are combined, the acid becomes neutralized by the base. The product of this reaction is an ionic compound, which is labeled as salt and water.
- Acids react with carbonates and bicarbonates to release salt, water, and carbon dioxide gas.
What is the real-life application of the physical properties of acids?
- In real life, the foods that we consume like citrus fruits, milk, vinegar, etc. get their characteristic sour taste from the acids.
- Acidic juices in our stomach are used to break down complex food into simpler molecules.
- Acid rain is said to be harmful due to the corrosive nature of the acids which are mixed with water.
What are the real-life applications of the chemical properties of acids?
- A combination of acids(Aqua Regia) is used to purify metal surfaces due to the corrosive property of acids.
- Acids are used to etch off metal surfaces like copper for designing propose or for purification
- The neutralization reaction of acid and base is used to generate different types of salt. You can read our article “7 types of salts” for more details.
See also
Dilute acids
Calculation of pH
Difference between acetic acid and glacial acetic acid
15 Properties of bases
