Acid rain or acid precipitation is the rain, snow, fog hail which has pH levels below 5.6, the average acidity of rain. The pH scale is used to measure the level of acidity by measuring the hydrogen ion concentration, were pH 1 is the strongest acid and pH 14 is the strongest base. Acids and bases of the same amount and strength can neutralise each other. Acid rain is caused by the release of oxides of sulphur (SO2) and nitrogen (NOx) which when combined with the moisture in the air, may fall as rain with acidity of sulphuric or nitric acids. …
