Toilet cleaner can be either an acid or a base, depending on the components it contains. It is more often a acid than a base, meaning that it measures less than seven on the pH scale, which measures the acidity or basicity of a solution.
Seven is the pH of pure water, a solution that is at equilibrium. Basic means that the solution has a high concentration of OH-minus ions and measures above seven on the pH scale. An acidic solution measures below seven and has a higher concentration of H-plus ions.
Most toilet bowl cleaners are acidic because acids are better for breaking down mineral stains, which are most likely what you are cleaning out of your toilet bowl. Surface cleaners, which you might use on the toilet seat or other parts of your home, tend to be basic so that they can pick up dirt and grease.
Basic chemicals are used in toilet cleaners when breaking down grease is a priority or when they need to have an affinity for water. Acidic cleaners can bond with minerals (such as those that help make up hard water stains) and remove minerals, limescale, and rust.
Look on the label of any cleaner if you are trying to figure out whether it is acidic or basic. The active ingredient, which should be listed at the top of the label on the back, will give you the answer-it will be either acidic or basic, and you can quickly look it up if you are unsure.
Toilet cleaner, because of the strong chemical components, can be damaging to skin and eyes, and can be lethal if ingested. Most acids are corrosive and can irritate eyes and skin. Ammonia and bleach are potentially fatal if ingested and can irritate skin, eyes, and the respiratory tract.