Example 配平方程式 Cr(OH)3(S)+Br2①+KOH÷KCrO4+KBr Solution Cr(OH)3 (s)+Br2 (1)->CrO2+Br Br2 (1)+2e=2Br ① Cr(OH);(s)+80H-=CrO2+30H-+4H2O+3e 即：Cr(OH3(s)+5OH=CrO42+4H0+3e ② ①×3+②×2得 2Cr(OH)3(s)+3Br2(1)+100H-=2CrO2-+6Br+8H2O 2Cr(OH)3(s)+3Br2(1)+10KOH=2K2CrO4+6KBr+8H2O 止页下页 节首 节尾14 Solution 配平方程式 Cr(OH)3 (s) + Br2 (l) + KOH K2CrO4 + KBr Cr(OH)3 (s) + Br2 (l) CrO4 2- + Br - Br2 (l) + 2e - = 2Br - ① Cr(OH)3 (s) + 8OH- = CrO4 2- + 3OH- + 4H2O + 3e - 即:Cr(OH)3 (s) + 5OH- = CrO4 2- + 4H2O + 3e - ② ①×3+②×2得 2Cr(OH)3 (s) + 3Br2 (l) + 10OH- = 2CrO4 2- + 6Br - + 8H2O 2Cr(OH)3 (s) + 3Br2 (l) + 10KOH= 2K2CrO4 + 6KBr + 8H2O Example