Acetylene is oxidised by permanganate in acidic solutions to liberate carbondioxide.

Explanation

a) The ionic skeleton equation is written as
`C_(2)H_(2)+MnO_(4)^(-)overset(H^(+))rarrCO_(2)+Mn^(2+)`
b) Writing oxidation numbers
`overset(-1)(C_(2))overset(+1)(H_(2))+overset(+7)(Mn)overset(-2)(O_(4)^(-))rarroverset(+4)(C)overset(-2)(O_(2))+overset(+2)(Mn^(+2))`
c) Locating atoms undergoing change in oxidation numbers
`overset(-1)(C_(2))H_(2)+overset(+7)(Mn)O_(4)^(-)rarroverset(+4)CO_(2)+overset(+2)(Mn^(+2))`
d) Dividing the reaction into two two halves and balancing in acidic medium, separately
Oxidation half - reaction : `C_(2)H_(2)rarrCO_(2)`
Step : 1 Balance carbon atoms
`_(2)H_(2)rarr2CO_(2)`
Step 2 : Balance oxygen atoms
`C_(2)H_(2)+4H_(2)Orarr2CO_(2)`
Step 3 : Balance hydrogen atoms
`C_(2)H_(2)+4H_(2)Krarr2CO_(2)+10H^(+)`
Step 4 : Balance charge
`C_(2)H_(2)+4H_(2)Orarr2CO_(2)+10H^(+)+10e^(-)" .....(a)"`
Reduction half - reaction : `MnO_(4)^(-)rarMn^(2+)`
Step 1 : Balance oxygen atoms
`MnO_(4)^(-)rarrMn^(2+)+4H_(2)O`
Step 2 : Balance hydrogen atoms
`MnO_(4^(-)+8H^(+)rarrMn^(2+)+4H_(2)O`
Step 3 : Balance charge
`MnO_(4)^(-)+8H^(+)+5e^(-)rarr Mn^(2+)+4H_(2)O" ...(b)"`
e) Equalising the electron and adding the two halves
`"eq(a) "xx1+"eq(b)"xx"2, we get"`
`{:(C_(2)H_(2)+4H_(2)Orarr2CO_(2)+10H^(+)+10e^(-)),(2MnO_(4)^(-)+16H^(+)+10e^(-)rarr2Mn^(2+)+8H_(2)O),(bar(C_(2)H_(2)+2MnO_(4)^(-)+6H^(+)rarr" ")),(" "2CO_(2)+2Mn^(2+)+4H_(2)O):}`
This is balanced equation.