p. 44 A.Q. 3abc p. 44 A.Q. 3abc 3a. What is an acid? What is a base? 3a. An acid is a compound that forms hydrogen (H+) ions in solution. A base forms hydroxide ions (OH-) in solution. 3b. The acid hydrogen fluoride (HF) can be dissolved in pure water. Will the pH of the solution be greater or less than 7? 3b. If an acid is dissolved in pure water, then the pH of the solution will be less than 7. 3c. During exercise, many chemical changes occur in the body, including a drop in blood pH, which can be very serious. How is the body able to cope with such changes? 3c. A drop in blood pH is countered by chemical buffers such as bicarbonate and phosphate ions.