Answer to Question #133290 in Biology for lesley love

Question

The pH of a solution describes its acidity or alkalinity: Describe how pH and H3O+ concentration are related and explain why diluting an acid raises the pH, but diluting a base lowers the pH.

Answer 1

Hydronium ion (H₃O⁺) is formed due to the interaction between a water molecule and a proton. Pure water dissociates into H₃O⁺ and OH^- ions at a constant rate creating an equilibrium of these ions (10^-7 M). Negative logarith of the H₃O⁺ concentration is called pH. As a result, pH of 7 indicates neutral solution where hydronium and hydroxide ions are at equilibrium. Adding an acid to the solution increase the concentration of protons and lowers pH value indicating an acidic solution. Diluting an acid results in the reduction of the hydronium ion concentration and raises the pH. In contrast, the presence of base in a solution increases the concentration of hydroxide ions that neutralise hydronium ion increasing pH. However, diluting a base leads reduces the concentration of hydroxide ions increasing the concentration of hydronium ions and lowering pH.