X,oxidization ability: Example: Cl+Br2CI+Br2
Cl2+Br- 2Cl-+Br2 X2 oxidization ability： Example:
reacts with water:two types of reactions Oxidization reaction:X,+2H,O->4HX+O, F2(vigorous)>Cl(slow under light)>Br2(extremely slow) Disproportionation reaction(without base): X2 +H2O=HXO+HX Cl2 >Br2 >I Ke(C12)=4.2×10-4Ke(B2)=7.2×10-9 KeL2)=2.0×10-13 We can see that the major constituent of the solution dissolved with Cl,Br2 and I is their elemental substance, respectively.氯水，溴水，碘水的主要成分是单质。 Presence of a base can promote dissolution and dispropor- tionation reaction在碱存在下，促进X,在H2O中的溶解、歧化
X2 + 2H2 O ⎯→4HX + O2 Disproportionation reaction(without base)： 2 2 2 Cl Br I We can see that the major constituent of the solution dissolved with Cl2 , Br2 and I2 is their elemental substance, respectively.氯水, 溴水, 碘水的主要成分是单质。 Presence of a base can promote dissolution and disproportionation reaction 在碱存在下，促进X2在H2O中的溶解、歧化。 • reacts with water：two types of reactions Oxidization reaction： 4 (Cl2 ) 4.2 10- K = 9 (Br2 ) 7.2 10- K = 13 (I2 ) 2.0 10- K = X2 + H2 O HXO + HX F2 (vigorous) > Cl2 (slow under light) > Br2 (extremely slow) I2
Products of disproportionation reaction of Br2 under basic condition X2+20H→X+XO+HO 3X0→2X+X03 3X2+60H→5X+X03+3H20 0.7665 0.5357 0.4556 1.0774 BrO. BrO B Br 0.5196
Products of disproportionation reaction of Br2 under basic condition + ⎯→ + + + ⎯→ + + - - - - 3X 6OH- 5X XO 3H O X 2OH X XO H O 2 3 2 2 2 _ 3XO- → 2X- + XO3 -
X2+2OH→X+XO+HO 3X2+60H→5X+X03+3H20 room low heated temperature temperature Cl2 C103 CIO C10 PH>4 Br2 BrO; BrO; BrO(0°C)PH>6 12 IO; I03 I03 PH>9 Elemental potential diagram for I2
room temperature heated low temperature I2 PH 9 - 3 IO - 3 IO - 3 IO Br PH 6 2 - BrO3 - BrO3 BrO (0 C) - O Cl2 ClO PH 4 3 - - ClO ClOElemental potential diagram for I2 ? + ⎯→ + + - 3X2 6OH- 5X XO3 3H2O _ + ⎯→ + + - - - X2 2OH X XO H2O
3.The preparation of the elemental substances F2 (g)electrolysis: The formal reaction: 2KHF2电→2KF+H,+E 十 HF The real reaction 2HFs ysis F2 +H2 Cl2(g)Industry method (electrolysis): 2NaCl+2H,0电解)>H2+CI2+2NaOH √Laboratory method: MnO,+4HCI-A >MnCl 2+Cl2 (g)+2H2O (concentrated)
•Cl2 (g) 2NaCl 2H O H2 Cl2 2NaOH 电解 + 2 ⎯⎯→ + + ✓Laboratory method： MnO2 + 4HCl ⎯→MnCl 2 + Cl2 (g) + 2H2 O ✓Industry method (electrolysis)： 3. The preparation of the elemental substances ： (concentrated) •F2 (g) electrolysis： 2 2 电解 2KHF 2 ⎯⎯→2KF+ H + F + HF The real reaction 2HF → F2 + H2 The formal reaction: electrolysis