1.

Balance the following reaction by oxidation number method.

Answer»

Solution :`MnO_(4)^(-1) +H_(2)S+H^(+) to MN^(2+)+S` (Acidic Medium).
(i) Write oxidation number of elements
`MnO_(4)^(-1) +H_2S to Mn^(2+)+S`
`(+7)(-2) (+1)(-2) (+2) 0`
(ii) Balance the number of atoms of the elements in which oxidation number changes
`MnO_(4)^(-1) +H_2S to Mn^(2+)+S`
`(+7) (-2) (+2) 0`
(iii) Decide the oxidation and REDUCTION reaction on the basis of difference of oxidation number.
Increase in oxidation number by 2 (Oxidation)

Decrease in oxidation number by 5( Reduction)
(IV) On multiplying oxidation reaction by 5 and reduction reaction by 2 to balance the change in oxidation number.
`2MnO_(4)^(-1) +5H_(2)S to 2Mn^(2+)+5S`
(v) Balance the electric charge and atoms which do not change in oxidation number (spectators).
`2MnO_(4)^(-1) +5H_(2)S+6H^(+) to 2Mn^(2+)+5S+8H_(2)O`
`2(-1)5(0)+6(+1)=2(+2)+5(0)+8(0)`
`-2+6=+4`
`+4=+4`
In the above reaction the reactants and products are balanced in terms of electric charge and mass EQUIVALENCE.


Discussion

No Comment Found