A student in a chemistry class was taking the final written exam. As he neared the end, he realized he was running out of time and wouldn't be able to perform the calculations necessary for the last problem worth ten points. It asked how to reduce 500 ml of a 0.3% HCl solution to a pH of 6.5. He quickly scribbled, "add an alkaline liquid" and put down his pencil just as the professor called for the end of the exam.
Several days later he got back his test and found no credit for the last problem. He went to the professor to ask for at least partial credit. The professor refused, pointing out that the exam instructions said to show all work, and he had been hoping for a formula with concentrations and quantities. What the student had written was just a basic solution.