explain why benzoic acid do not affect litmus paper
I don't know why it won't. You may have used the wrong color litmus paper to start.
Benzoic acid, a common white crystalline organic compound, typically does not affect litmus paper due to its chemical properties. To understand why, let's discuss the nature of litmus paper and benzoic acid.
Litmus paper is a pH indicator made of a special type of paper that is saturated with a mixture of natural dyes extracted from lichens. These dyes are sensitive to changes in pH, which is a measure of the acidity or alkalinity of a solution. Litmus paper turns red in acidic solutions (pH less than 7), blue in alkaline solutions (pH greater than 7), and remains purple in neutral solutions (pH around 7).
On the other hand, benzoic acid is a weak acid with a slightly acidic pH of around 2.5-3.5. It is often used as a food preservative and has various applications in industries such as pharmaceuticals and cosmetics. Despite being an acid, benzoic acid may not always show any visible effect on litmus paper. This is mainly because benzoic acid is a weak acid, meaning it does not readily release many hydrogen ions (H+) in an aqueous solution.
When litmus paper comes into contact with a strong acid (such as hydrochloric acid), a significant amount of hydrogen ions are released, resulting in a visible change in color. However, with weak acids like benzoic acid, only a small number of hydrogen ions are released, which might not be enough to cause a noticeable reaction with the litmus paper. Consequently, benzoic acid tends to have a limited effect on litmus paper and may not cause a color change.
In summary, benzoic acid does not significantly affect litmus paper due to its weak acidic nature, which results in a relatively small release of hydrogen ions when dissolved in water.