61. A measure of acidity or alkalinity of water soluble substances. A pH value is a number from 1 to 14, with 7 as the middle point. Values below 7 indicate acidity which increases as the number decreases, 1 being the most acidic.
62. The pH scale typically ranges from 1 to 14, with lower numbers representing acids, higher numbers, bases. Neutral liquids like water have a pH of 7.
63. The pH scale ranges from 0 to 14.
64. A major problem with the use of fertilizers occurs when they’re washed off the land by rainwater into rivers and lakes.