в)

1

2Cr+M- бе" = 2Сг+3

3

2СГ - 2е" = Cl?

K2Cr2O7 + HHCl = 2KCl + 2CrCl3 + 7H2O + 3Cl2

&

1

Cr2O7" + 14H++ бе"

= 2Cr3+ + 7H2O

3

2Cl" - 2е" = Cl2

Cr2O7- + 6Cl" + 14H+ =

= 2Cr3++ 3Cl2+ 7H2O

г)

5

S+4-2e"=S+6

2

Mn+7+ 5е" = Mn+2

5SOl" +2MnOi+ 6H+

= 5SO4" + 2Mn2+ + 3H2O

5

S02" + H20-2e"==

SO4" + 2H+

2

MnO4" + 8Н+ + 5е~ =

= Mn2+ + 4H2O

5SO3" + 2MnO4 + 6H+

= 5SO4" + 2Mn2+ + 3H2O

д)

1

Cr+3 - Зе" = Cr+6

1

Mn+7 + Зе- = Mn+4

Cr3+ + MnO4" + 3H2O =

= CrO4" + H2MnO3 + 4H+

1

Cr3+ + 4H2O - Зе" =

= CrO4" + 8H+

1

MnOi + 3H2O + Зе"

= H2MnO3 + 40Н"

Cr3+ + MnOi + 3H2O =

= CrO4" + H2MnO3 + 4H+

е)

5

2Br" —2е" = Вг2

1

2I+5+ 10е~ = 1°,

H)Br" +21O3" + 12H+ =

= 5Br2 + I2+ 6H2O

5

2Вг"-2е~ = Вг2

1

2Ю3" + 12H+ +• 1Oe" =

= I2 + 6H2O