3.1 Review of Acids and Bases and Ka
3.1 閰哥⒈鍜孠a鐨勫洖椤�

The most commonly applied definition of acids and bases is the Br酶nsted-Lowry definition:
鏈€甯哥敤鐨勯吀鍜岀⒈瀹氫箟鏄� Br酶nsted-Lowry 瀹氫箟锛�

• Br酶nsted-Lowry Acid: a substance that can donate a proton (H+)
  Br酶nsted-Lowry Acid锛氫竴绉嶅彲浠ユ彁渚涜川瀛愮殑鐗╄川锛圚 + 锛�

• Br酶nsted-Lowry Base: a substance that can accept a proton (H+)
  Br酶nsted-Lowry 纰憋細鍙互鎺ュ彈璐ㄥ瓙鐨勭墿璐� (H + )

Therefore, according to the Br酶nsted-Lowry definition, an acid-base reaction is a proton transfer process in which the acid gives away a proton and the base accepts a proton as shown in the general equation:
鍥犳锛屾牴鎹� Br酶nsted-Lowry 瀹氫箟锛岄吀纰卞弽搴旀槸涓€涓川瀛愯浆绉昏繃绋嬶紝鍏朵腑閰告斁鍑鸿川瀛愶紝纰辨帴鍙楄川瀛愶紝濡傞€氬紡鎵€绀猴細

General equation for acid-base reaction
閰哥⒈鍙嶅簲鐨勪竴鑸柟绋�

The species that forms when an acid loses its proton is called the conjugate base of that acid; similarly, the species that forms when a base accepts a proton is called the conjugate acid of that base. In the general equation above, HA is the conjugate acid of A鈥�, and A鈥� is the conjugate base of HA. HA and A鈥� can also be called a conjugate acid-base pair; another pair is HB+ and B.
褰撻吀澶卞幓璐ㄥ瓙鏃跺舰鎴愮殑鐗╄川绉颁负璇ラ吀鐨勫叡杞⒈锛涘悓鏍凤紝褰撶⒈鎺ュ彈璐ㄥ瓙鏃跺舰鎴愮殑鐗╄川绉颁负璇ョ⒈鐨勫叡杞吀銆傚湪涓婇潰鐨勯€氬紡涓紝HA鏄疉 鈥� 鐨勫叡杞吀锛孉 鈥� 鏄疕A鐨勫叡杞⒈銆� HA鍜孉 鈥� 涔熷彲绉颁负鍏辫江閰哥⒈瀵癸紱鍙︿竴瀵规槸 HB + 鍜� B銆�

A strong acid donates the proton completely, and the arrow 鈥溾啋鈥� can be used in the reaction equation to indicate that the reaction goes to completion. The dissociation reaction of the strong acid HCl in water is used as an example here:
寮洪吀瀹屽叏缁欏嚭璐ㄥ瓙锛屽弽搴旀柟绋嬪紡涓彲鐢ㄧ澶粹€溾啋鈥濊〃绀哄弽搴斿畬鍏ㄣ€傝繖閲屼互寮洪吀鎬Cl鍦ㄦ按涓殑瑙ｇ鍙嶅簲涓轰緥锛�

HCl (g) + H2O (l) 鈫扝3O+(aq) + Cl鈥�(aq)

For weak acids (HA is used as a general formula), the proton is only partially donated and the reaction stays at equilibrium. The equilibrium arrow 鈥�鈥� will be needed in the reaction equation to indicate the equilibrium status:
瀵逛簬寮遍吀锛圚A鐢ㄤ綔閫氬紡锛夛紝浠呮彁渚涢儴鍒嗚川瀛愶紝鍙嶅簲淇濇寔骞宠　銆傚弽搴旀柟绋嬩腑闇€瑕佸钩琛＄澶粹€� 鈥濇潵鎸囩ず骞宠　鐘舵€侊細

HA (aq) + H2O (l) 鈬� H3O+ (aq) + A鈥� (aq)

The equilibrium constant for the above reaction is called the acid dissociation constant, Ka. It is a constant to measure the relative strength of an acid. The expression for Ka is:
涓婅堪鍙嶅簲鐨勫钩琛″父鏁扮О涓洪吀瑙ｇ甯告暟锛孠 a. 瀹冩槸琛￠噺閰哥浉瀵瑰己搴︾殑甯告暟銆� K a 鐨勮〃杈惧紡涓猴細

The larger the Ka value, the stronger the ability of the acid to donate protons, and the stronger the acid is. (Technically, when the Ka value is larger than 10, the acid can be regarded as a strong acid.)
K a 鍊艰秺澶э紝閰歌础鐚川瀛愮殑鑳藉姏瓒婂己锛岄吀瓒婂己銆� 锛堜粠鎶€鏈笂璁诧紝褰揔 a 鍊煎ぇ浜�10鏃讹紝閰稿彲浠ヨ瑙嗕负寮洪吀銆傦級

For the conjugate acid-base pair, the stronger the acid, the weaker the conjugate base is, and vice versa.
瀵逛簬鍏辫江閰哥⒈瀵规潵璇达紝閰歌秺寮猴紝鍏辫江纰辫秺寮憋紝鍙嶄箣浜︾劧銆�