AP BIOLOGY

Detailed explanation-1: -It indicates the concentration of hydrogen ions (H+) and hydroxide ions (OH-) in a solution. These ion concentrations are equal in pure water, which has a pH of 7. This pH value of 7 is important because it indicates a neutral solution. All other substances are compared to this neutral point.

Detailed explanation-2: -Answer and Explanation: The compound with equal hydroxyl and hydrogen ions is pure water. Pure water is typically a solvent that has a similar number of both hydrogen and hydroxide ions. It is thus a neutral solution and thus has been considered to be universal.

Detailed explanation-3: -a) In a neutral solution, the concentration of H+ and OH-are equal.

Detailed explanation-4: -Adding equal amounts of H+ and OH-to water will also be neutral with a pH of 7, because most of these ions combine to form water molecules and the remaining H+ and OH-ion concentration is equal and very low.

Detailed explanation-5: -An acidic solution has a high concentration of hydrogen ions (H +start superscript, plus, end superscript), greater than that of pure water. A basic solution has a low H +start superscript, plus, end superscript concentration, less than that of pure water.