Water, sugar and table salt are common examples of neutral substances. The pH scale rates substances based on how acidic or basic they are. A substance that is not acidic or basic is described as a neutral substance.
Acids and bases are the two extremes that are used to describe the chemical properties of any specific chemical. Acids taste sour, react strongly with metal and, if the acid is strong enough, can burn skin. Bases taste bitter, feel slippery and can also burn skin when strong enough. Mixing acids and bases, however, can neutralize the extreme effects of the substances.
The pH scale rates items on a scale of 0 to 14. Neutral substances are rated 7 on the scale. Substances with a pH below 7 are acidic, and those with a pH above 7 are basic. The lower the number, the stronger the acid is. The higher the number, the more basic the chemical is.
Pure water is a neutral substance, but other substances often mix with water and change its pH value. If an acidic substance like vinegar or lemon juice is added to the water, it will become acidic. If lye, ammonia or another basic substance is added to the water, the mixture becomes basic.