Question

please balance this equation by oxidation no method

Answer 1

Oh Good. Wonderful Equation to balance. Most of the students used to confuse in this equation, How to balance it.

Balancing.

Steps of Balancing from Oxidation number method.  

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Step 1. First Write the Given Redox Reaction.

  Cr(OH)₃ + IO₃⁻ ------- I⁻ + CrO₄²⁻  (write the oxidation state also.)

Step2.  Identify Oxidation and Reduction half Reaction.

       IO₃⁻ ------- I⁻ [Reduction]     [Changes by 6 unit]

(Oxidation number of Iodine is changing.)

Cr(OH)₃ ------- CrO₄²⁻   [Oxidation]  [Changes by 3 unit]

(Oxidation number of the Cr is changing)

Step 3 .Multiply 1st equation by 1 and second equation by 2.

  2Cr(OH)₃ ------- 2CrO₄²⁻

            IO₃⁻ ------- I⁻

 Step 4. Now, Add both the equations,

∴  2Cr(OH)₃ +   IO₃⁻  ------- 2CrO₄²⁻ + I⁻

Step 5.  Now, Add the OH⁻ ions on L.H.S. and Water on R.H.S. , since this reaction will be in basic medium.

∴  2Cr(OH)₃ +   IO₃⁻  + 4OH⁻ ------- 2CrO₄²⁻ + I⁻  + 5H₂O

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Hope it helps.