Oksidlanish-qaytarilish reaksiyalarining turlari

₄+  6H=  5NO₂  +2Mn  + 2H₂O

                    _{+                    +                 2-             +                        2-              +            2-}

               +5K       2K+   3SO₄     5K         2SO₄+    2K  SO₄

 

                  5KNO₂+2KMnO₄+3H₂SO₄=5KNO₃+2MnSO₄+K₂SO₄+3H₂O

                 Oxirgi tenglama oksidlanish-qaytarilish reaksiyasining to’liq molekular

     tenglamasi hisoblanadi.

                   Misol 2.

                          _{+7                   +4                                        +2                        +6}

                   2KMnO₄+5K₂SO₃+3H₂SO₄=2MnSO₄+6K₂SO₄+3H₂O

                   

                       Mn⁺⁷   +5e             ®Mn⁺²          2

                       

                        S⁺⁴      +2e          ®S⁺⁶                5

                    Yarim reaksiya usulida  tenglashtirilsa:

                2KMnO₄+3Na₂SO₃+H₂O=3Na₂SO₄+2MnO₂+2KOH

                                       _{-                2-                                                 2-}

                                MnO₄+   SO₃+H₂O→MnO₂+ SO₄+……

         Oksidlovchi uchun (2) qoidani va qaytaruvchi uchun (3) qoidani qo’llab yarim    reaksiyalarni yozamiz:

                       _{-                                      -}

                MnO₄+2H₂O+3e=MnO₂+4OH              2

                     _{2-                                    2-         +}

              SO₃+H₂O-2e=SO₄+2H                          3

 

                      _{-            2-                                                2-               -}

        2MnO₄+3SO₃+H₂O=2MnO₂+SO₄+2OH

         To’liq molekulyar tenglama yozish uchun mos ionlar qo’shiladi.

                     2KMnO₄+3Na₂SO₃+H₂O=3Na₂SO₄+2MnO₂+2KOH

            Vodorod peroksidi oksidlanish-qaytarilish reaksiyalarida  sharoitga qarab ham  oksidlovchi ham qaytaruvchi xossasini namoyon etadi. Kuchli qaytaruvchilar bilan  vodorod peroksidi oksidlovchi va reaksiya muhitiga qarab quyidagicha qaytariladi:

1)     kislotali muhitda vodorod peroksidi vodorod ioni bilan bog’lanib suv   

 molekulasini hosil qiladi.

                                     H₂O₂+2H⁺₊2e®2H₂O

2)     neytral va ishqoriy sharoitda vodorod peroksidi o’ziga ikkita elektron qabul qilib  gidroksid ionini hosil qiladi.

                                              _-

                                Н₂О₂+2е   ®2ОН

 

      Misol 3.         Н₂О₂+FeSO₄+H₂SO₄ →Fe₂(SO₄)₃+H₂O

             

                                 Fe²⁺-2e=Fe^{3 +}                         2

                       

                                H₂O₂+2H⁺ + 2e=2H₂O           1

                                2Fe²⁺+H₂O₂+2H⁺=2Fe³⁺+2H₂O

                 Bu reaksiya molekula holda quyidagicha yoziladi:

                         H₂O₂+2FeSO₄+H₂SO₄=Fe₂(SO₄)₃+2H₂O

        Misol 4.                 2KJ+H₂O2  →J₂+2KOH

                     2J ^--2e=J₂             1

                     H₂O₂+2e=2OH^-  1

       Misol 5.      2NaCrO₂+3H₂O₂+2NaOH=2Na₂CrO₄+4H₂O

                                _{-                 -                     2-}             

                     CrO₂+4OH-3e=CrO₄+2H₂O               2

                        H₂O₂+2e=2OH^-                               3

                             _{-               -                                    2-}  

                2CrO₂+2OH+3H₂O₂=2CrO₄+4H₂O

              Vodorod peroksidi kuchli oksidlovchilar bilan (KMnO₄, (NH₄)₂Cr₂O₇,K₂Cr₂O₇    

             va bosqalar)  bilan qaytaruvchi bo’lib reaksiyaga kirishadi va oksidlanadi.

1)     kislotali muhitda vodorod peroksidi o’zidan ikkita elektron berib kislorod   molekulasini hosil qiladi va oksidlanadi.             

                                        Н₂О₂-2е=О₂+2Н^-

      2)ishqoriy sharoitda vodorod peroksidi o’ziga ikkita elektron biriktirib  kislorod va suv molekulasini hosil qiladi.          

                         Н₂О₂+2ОН ^--2е=О₂+2Н₂О+

          Misol   6.               Н₂О₂+МnO₄^-+H⁺→O₂+Mn²⁺…….

                   Н₂О₂-2e=O₂+2H ⁺                              5

                  MnO₄^-+8H⁺+5e=Mn²⁺+4H₂O             2

          5H₂O₂+2MnO₄^-+6H⁺=5O₂+2Mn²⁺+8H₂O

          5H₂O₂+2KMnO₄+3H₂SO₄=5O₂+2MnSO₄+H₂SO4+8H2O  

 

        Misol 7.                 H₂O₂+[Fe(CN) ₆]^3-+OH^-=O₂+[Fe(CN)₆]^4-+………

                      H₂O₂+2OH^--2e=O₂+2H2O                          1

                    [ Fe(CN)₆]^3-+1e=[Fe(CN)₆]^4-                           2

                          H₂O₂+2OH^-+2[Fe(CN)₆] ^3-=O₂+2H₂O+2[Fe(CN)₆]^4-

                          H₂O₂+2K₃[Fe(CN)₆]+2KOH=O₂+2K₄[Fe(CN)₆]+2H₂O