1.

Iodate oxidises chromic hydroxide and gives iodide and chromate in basic medium.

Answer»

Solution :(a) The ionic SKELETON equation is written as
`IO_(3)^(-) +Cr(OH)_(3) OVERSET(OH^(-))to I^(-)+CrO_(4)^(2-)`
(b) Writing oxidation numbers
`overset(+5)(I) overset(-2)(O_(3)^(-)) +overset(+3)(Cr) overset(-2 +1)(OH_(3)) to overset(-1)(I^(-))+overset(+6)(Cr) overset(-2) (O_(4)^(-2))`
(c) Locating atoms undergoing change in oxidation numbers.
`overset(+5)(IO_(3)^(-)) +overset(+3)(Cr(OH)_(3)) to overset(-1) (I^(-)) +overset(+6)(Cr) O_(4)^(-2)`
(d) Dividing the reaction into two halves and balancing in ACIDIC medium, separately.
(e) Equalising the ELEMENTS and adding the two halves
`eq (a) xx 2+eq (b) xx 1," we get"`
`2Cr(OH)_(3)+10OH^(-) to 6e^(-)+2CrO_(4)^(2-)+8H_(2)O`
`IO_(3)^(-)+6H_(2)O+6e^(-) to I^(-)+6OH^(-)`
`IO_(3)^(-)+2Cr(OH)_(3)+4OH^(-) to I^(-)+2CrO_(4)^(2-)+5H_(2)O`
This is the balanced equation.


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