Here's a breakdown:

* Acids: Have a pH less than 7, meaning they have a high concentration of hydrogen ions (H+).

* Neutral substances: Have a pH of 7, meaning they have an equal concentration of hydrogen and hydroxide ions (OH-).

* Bases: Have a pH greater than 7, meaning they have a high concentration of hydroxide ions (OH-).

What happens when you add a neutral substance to an acid?

* No significant change in pH: The neutral substance won't contribute significantly to either the hydrogen or hydroxide ion concentration.

* Dilution: Adding any substance to an acid will dilute it, meaning the concentration of H+ ions will decrease slightly. However, this change in pH is usually minor, especially if the amount of neutral substance added is small.

* Potential for reaction: In some cases, the neutral substance might react with the acid. For example, adding water to a strong acid like sulfuric acid can generate heat due to the reaction.

Examples of Neutral Substances:

* Water (H2O)

* Sugar (C12H22O11)

* Salt (NaCl)

Important Note: If you add a base to an acid, you will have a neutralization reaction, which will raise the pH of the solution towards neutrality.