The properties of most acids, especially in water solutions, arise from the hydrogen ion (H+, also referred to as the hydronium ion, H3O+, the form in which H+ is found in a water environment).

• 大多数酸尤其是在水溶液中的酸，其各种性质都是因存在氢离子（H+，亦可产生水合氢离子H3O+，因此任何水的环境都可发现氢离子）而产生的。