Difference Between Acid and Alkaline

Main Difference

The main difference between acid and alkaline is that acid has low pH lies below pH 7, whereas alkaline has high pH lies above pH 7.

Acid vs. Alkaline

Acid is a chemical that has low pH lies below pH 7 whereas the alkaline solution is a chemical which has high pH lies above pH 7. An acid solution is composed of H+ ions, while the alkaline solution is composed of OH- ions. Acid has sour taste where the taste of alkaline solution is bitter. The texture of acid is sticky; on the other hand, alkaline is slippery in texture. Bases can neutralize an acid; on the contrary, acid can neutralize the alkaline solution. The acid rest on the concentration of the hydronium ions; conversely, alkaline depends on the concentration of hydroxide ions. Phenolphthalein in acid solution remains colorless while phenolphthalein in alkaline solution makes it pink. Acid changes litmus paper into red, whereas alkaline changes litmus paper into blue. Acid is frequently used as an electrolyte in batteries, to remove rust from metals, to produce fertilizers, for mineral processing; on the flip side, alkaline is mainly used in cleaning as laundry detergent, as dishwashing, and as stain removers. Some common examples of the acid include sulfuric acid, hydrochloric acid, and acetic acid, etc. while examples of alkaline include sodium hydroxide, potassium hydroxide, and magnesium hydroxide.

Comparison Chart

AcidAlkaline
An acid is a chemical specie which donates a proton.An alkaline is any substance which accepts a proton.
pH
Lower than pH 7Higher than pH 7
Strength
Rest on the concentration of the hydronium ionsDepends on the concentration of hydroxide ions
Ions Present
Composed of H+ ionsComposed of OH- ions.
Taste
Sour in tasteBitter in taste
Texture
StickySlippery
Neutralization
Neutralized by basesNeutralized by acids
Phenolphthalein
Remains colorlessChanges into pink
Examples
Sulfuric acid, hydrochloric acid, and acetic acid, etcSodium hydroxide, potassium hydroxide, and magnesium hydroxide.

What is Acid?

By Arrhenius definition, “an acid is a chemical specie which when dissolved in water gives hydrogen ions in a solution activity greater than in pure water.” Bronstein Lowry defines an acid as a substance which donates a proton. Acid has low pH lower lies below pH 7. It has a sour taste. Acid depending on temperature can occur in solid, liquid, and gaseous form. It is a chemical specie that can be neutralized by a base. In an aqueous solution, they are capable of releasing protons or H+ ions. Frequently, compounds that can accept electrons from a donor are known as Lewis acid. Lewis acid means that some compounds that do not contain H+ ions are also considered as acids. For example, aluminum trichloride (AlCl3) is a Lewis acid. Acid turns litmus paper into the red. Many acids react with metals as they have a corrosive effect on them, forming hydrogen gas (H2) and a salt. Phenolphthalein in acid solution remains colorless. The acid rest on the concentration of the hydronium ions. Acid is frequently used as an electrolyte in batteries, to remove rust from metals, to produce fertilizers and gasoline, for mineral processing, and as additives in food and beverages.

Types

  • Strong Acids: That can dissociate completely into its ions.
  • Weak Acids: That partially dissociate into its ions.

Examples

Sulfuric acid, Hydrochloric acid, Nitric acid, Acetic acid, Lactic acid, and Citric acid.

What is Alkaline?

By Arrhenius definition, “an alkaline is an aqueous substance that can accept hydrogen ions.” Bronstein Lowry also defines alkaline as any substance which accepts a proton. Alkaline has high pH lies above pH 7. It means alkaline solutions show basic properties because of high pH. So, acid can neutralize the alkaline solution. It has a bitter taste. By texture, alkaline is slippery due to the reaction of alkaline with the oils of our hand. Some solids alkaline except ammonia, are gas. When alkali is dissolved in water, an alkaline solution is formed. Alkali refers to a salt of alkali metals or alkaline earth metals.

The alkaline word is derived from metal elements in group 1 and group 2. The elements of group 1 in the periodic table are called alkali metals. Group 2 elements are called alkaline earth metals. Both these type of metals, when added to water, cause its pH to be increased, because of reaction with water molecules to form metal hydroxide and H2 gas. This metal hydroxide increases the pH of the solution; meanwhile, the concentration of OH- ions increases. Due to the indication of basicity of alkaline solution, it turns red litmus paper into the blue. Some are corrosive, but some alkaline solutions are not.

Examples

Sodium hydroxide, Potassium hydroxide, and Magnesium hydroxide.

Key Differences

  1. Acid is a chemical specie that has low pH lies below pH seven, whereas the alkaline solution is a chemical which has high pH lies above pH 7.
  2. An acid solution is composed of H+ ions, while the alkaline solution is composed of OH- ions.
  3. Acid has sour taste where the taste of alkaline solution is bitter.
  4. The texture of acid is sticky; on the other hand, alkaline is slippery in texture.
  5. Bases can neutralize an acid; on the contrary, acid can neutralize the alkaline solution.
  6. The acid rest on the concentration of the hydronium ions; conversely, alkaline depends on the concentration of hydroxide ions.
  7. Phenolphthalein in acid solution remains colorless while phenolphthalein in alkaline solution makes it pink.
  8. Acid changes litmus paper into red, whereas alkaline changes litmus paper into blue.
  9. Acid is frequently used as an electrolyte in batteries, to remove rust from metals, to produce fertilizers, for mineral processing; on the flip side, alkaline is mainly used in cleaning as laundry detergent, as dishwashing, and as stain removers.
  10. Some common examples of the acid include sulfuric acid, hydrochloric acid, and acetic acid, etc. while examples of alkaline include sodium hydroxide, potassium hydroxide, and magnesium hydroxide.

Conclusion

Above discussion concludes that acid has low pH lies below pH seven, whereas alkaline has high pH lies above pH 7.

Author:

Harlon Moss

Harlon currently works as a quality moderator and content writer for Turpy Media. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss or on Pinterest @HarlonMoss

View all posts by Harlon Moss