在化学上常采用氢离子(H~+)浓度的负对数来表示溶液的酸碱性,叫做溶液的pH值。pH=-lg(H)。例如纯水:[H~+]=[OH~+]=1×10~(-7)M。它的pH值是:pH=-lg10~(-7)=-(-7)。通常可用酸碱指示剂、pH试纸或pH计来测得溶液的pH值。pH值为7时,溶液呈中性;pH值小于7时,溶液中氢离子数量多于氢氧根离子数量,溶液呈酸性;pH值 In chemistry, the negative logarithm of hydrogen ion (H ~ +) concentration is often used to indicate the pH value of a solution. pH = -lg (H). For example, pure water: [H ~ +] = [OH ~ +] = 1 × 10 -7 M. Its pH is: pH = -lg10 ~ (-7) = - (- 7). The pH value of the solution can usually be measured with a pH indicator, pH test strip, or pH meter. When the pH value is 7, the solution is neutral. When the pH value is less than 7, the amount of hydrogen ions in the solution is more than the amount of hydroxide ions and the solution is acidic. The pH value