Why does pure dry benzoic acid does not affect a litmus paper
https://www.jiskha.com/questions/1795757/Explain-why-pure-dry-benzoic-acid-does-not-affect-a-litmus-paper
Litmus paper is an indicator for the presence of an acidic solution (blue litmus => red) or alkaline solution (red litmus => blue). To understand this it is important to note that for a substance to become an acid or base two conditions must apply; that is, (1) the substance of interest must have water as a solvent which (2) effects ionization of the substance to yield hydronium ions (H₃O⁺ = H⁺) for an acidic solution or hydroxide ions (OHˉ) for an alkaline solution. Since benzoic acid in solid form is not in water, it will not ionize to deliver H⁺ ions into solution and litmus will be unable to detect H⁺ ions and change color.
Pure dry benzoic acid does not affect a litmus paper because it is a weak acid and does not release hydrogen ions (H+) in water. Litmus paper is a commonly used indicator in chemistry, which changes color depending on the presence of hydrogen ions or hydroxide ions in a solution.
To understand why benzoic acid does not affect a litmus paper, it is important to know about the properties of acids and bases. Acids are substances that release hydrogen ions (H+) when dissolved in water, while bases release hydroxide ions (OH-). Litmus paper is specifically used to test for the presence of acid or base in a solution.
However, not all substances that are classified as acids will have a noticeable effect on litmus paper. The strength of an acid is determined by its ability to release hydrogen ions. Strong acids, such as hydrochloric acid (HCl), sulfuric acid (H2SO4), or nitric acid (HNO3), dissociate almost completely in water, resulting in a large concentration of hydrogen ions. As a result, litmus paper will change color when it comes into contact with these strong acids, indicating acidity.
On the other hand, weak acids like benzoic acid (C6H5COOH) only partially dissociate in water, releasing a smaller concentration of hydrogen ions. This low concentration is often not enough to produce a noticeable effect on litmus paper. Therefore, when pure dry benzoic acid is applied to a litmus paper, it will typically not change its color, indicating that it is a weak acid.
In summary, the reason pure dry benzoic acid does not affect a litmus paper is that it is a weak acid with a low concentration of hydrogen ions when dissolved in water. This low concentration is insufficient to cause a change in the color of the litmus paper.