The Lewis concept of acids and bases
强调 电子 对 物种
概念
emphasizes the shared electron pair rather than the
proton . A Lewis acid is any species that accept an electron pair , and a Lewis base is any species that
金属
and a metal hydroxide produces water and a salt .
最早对酸碱的定之一是由阿列纽斯提出的。一种阿列 纽斯算指的是那些溶解在水中之后，增加氢离子浓度的物 质。在描述酸碱反应中为了记录方便，化学家们常常用H+ 来代表氢离子，但是自由氢核质子不能单独存在于水中， 它将以水合氢离子的形式存在在水中。一种阿列纽斯碱是 指那些溶解于水之后能够能加氢氧根浓度的离子氢氧化合 物，其中最常见的有氢氧化钠，氢氧化钾和氢氧化钙。因 为水中存在着平衡的关系，当其中一个离子（氢离子）的 浓度上升，另外一种离子（氢氧根离子）的浓度将会下降 。 当其中一种酸和一种碱混合在一起，酸碱中和反应就 发生了。一般来说，一个酸碱中和反应就是一种酸和一种 碱生成盐的反应。
不同的酸能够电离出来的氢离子的数量是不一样的，像盐酸和硝酸这样的就被称为 一元酸。多元酸能够产生出2个或者2个以上的氢离子，就像硫酸这样。根据布朗斯特的 酸碱理论，一种酸如果能够容易的释放出氢离子，那这种酸的酸性就比较强。而它的共 轭碱的碱性就比较差。强酸能够完全电离出氢离子作为水合氢离子存在于水中。实际上 ，是水的电离能力被限制了。术语上的电离能力影响就是指溶剂的电离能力会被溶解在 它之中的强酸或者强碱所制约。强碱将会限制溶剂的酸性，而弱碱则将溶剂分化为酸。
记录 指代
Note that chemists often write H+(aq) and refer to the
hydrogen ion when describing acid-base reactions
自由 质子 水合氢 阿列纽斯 碱
氢
核 存在
but the free hydrogen nucleus , a proton , does not exist alone in water ,it exists
definitions of acids and bases , and the most
阿列纽斯酸碱理论 路易斯酸碱理论 酸碱质子理论
common ones are Arrhenius , bronsted-Lowry and Lewis definitions .
One of the first definitions of acids and bases was
3.Water is an amphoteric substance ， one that can function as both a a BronstedLowry acid and a base., depending on the substance with which reacts .
水是一种可以同时作为一种布朗斯特酸或者布朗斯特碱作用的两性物质，至于水 在反应中是作为一种酸还是一种碱，就要由与其反应的物质而决定了。
（由于段落过长，所以在这里不采用逐字逐句的分析，只是列出一些重点内容） 1.The bronsted-Lowry concept emphasizes the transfer of a proton (H+) from an acid to a base . 酸碱质子理论强调的是酸和碱之间质子的传递 2.A Bronsted-Lowry acid is a substance that can donate a proton , a bronstedLowry base is a substance that can accept a proton . 一种布朗斯特酸是指可以给出氢质子的物质，而一种布朗斯特碱是指可以接收氢 离子的物质
阿列纽斯酸
suggested by Arrhenius . And Arrhenius acids is a
物质 浓度 溶解
substance that increases the concentration of the hydrogen ion , H+（aq）， when dissolved in water .
4.The removal of a proton from a Bronsted-Lowry acid produces its conjugate base , which is the acid with a hydrogen ion removed , and the reception of a proton by a Bronsted-Lowry base produces its conjugate acid , which is the base with a hydrogen ion added . Together , an acid and its conjugate base are called a conjugate acid-base pair . 一个布朗斯特酸去除一个质子将会变成它的共轭碱，也就是一个失去一个氢离子的 酸。一个布朗斯特碱接收一个质子将会变成它的共轭酸，也就是一个得到一个氢离子的 碱。总的来说，一个酸与它的共轭碱就被合称为一个共轭酸碱对。 5.Water itself dissociates into ions , H+(aq) and OH-(aq),very slightly in an equilibrium process known as autoionization . The extent of this autoionization is expressed by the ion-product constant for water : Kw=[H+][OH-]=1.0x10-14 水本身处在一个电离平衡之中，它会电离出少量的游离氢离子和氢氧根离子。水电 离的程度用水的电离常数来描述。在25十摄氏度下计算公式为： Kw=[H+][OH-]=1.0x10-14 6.The acidity or basicity of something , therefore , can be measured by its hydrogen ion concentration . PH is a logarithmic measure of the acidity of an aqueous solution . PH= - log[H+] 物质的酸度和碱度可以用它的氢离子浓度来测量，PH就是一个用于测量水溶液中酸 度的对数。 PH= - log[H+]
The Lewis concept is more general than the Bronste d-Lowry concept because it greatly expands the
classes of acids . Many species that do not contain
分子ds can ionize to form different numbers of H+ (aq) ions . Acids like HCl and HNO3 are called monoprotic acids which yield one H+(aq) Polyprotic acids yield two or more H+(aq) , such as H2SO4 . According to the Bronsted-Lowry concept ，the acid which is easy to donate proton is called a strong acid while its conjugate base is weak. Strong acids dissociate completely to yield H30+ in water ; in effect , water equalizes (Levels) their strengths . The term leveling effect refers to a solvent’s ability to level the effect of a strong acid or base dissolved in it . Strong bases are leveling solvents for acids , weak bases are differentiating solvents for acids.
奉献
donates an electron pair . The product of any Lewis
加合物
acid-base reaction is called an adduct , a single
共价键
species that contains a new covalent bond .
H in their reactions . Molecules with polar double bonds act as Lewis acids , as do those with
缺电子 原子
electron-deficient atoms . Metal ions act as Lewis acids when they dissolve in water , which acts as a
When a solution of an acid and that of a base are
中和 发生
mixed ， a neutralization reaction occurs ， In general ， a neutralization reaction between an acid