For the reaction, shown below, determine which statements are True and which are

Question

For the reaction, shown below, determine which statements are True and which are False.

3Fe(s) + Cr2O72-(aq) +14H+(aq) 3Fe2+(aq) + 2Cr3+(aq) + 7H2O(l)       o=1.77V

True False  The oxidation state of chromium in dichromate is +3.
True False  The oxidation state of hydrogen changes from +1 to 0.
True False  The reducing agent is Fe2+ (aq)
True False  The oxidizing agent is Fe2+ (aq)
True False  The chromium half-reaction takes place in a neutral solution.
True False  The highest oxidation state for oxygen in this reaction is 0.

Please help & explain.

Explanation / Answer

1) The oxidation state of chromium in dichromate is +3. ( False)

reason : Cr2O7-2

               2x + 7 x (-2) = -2

               x = +6

Cr oxidation state in dicromate = +6

2)    The oxidation state of hydrogen changes from +1 to 0. (False)

reason :

in reactant : H+ here hydrogen oxidation state = +1

in products : H2O , here 2x -2 = 0

                                       x = +1

here also oxidation state +1

no change in oxidation state of hydrogen

3)    The reducing agent is Fe2+ (aq) (False)

Fe --------------------> Fe+2   + 2e-

it oxidation reaction

Fe--------------> reducing agent

Fe+2 --------------> oxidising agent

4) The oxidizing agent is Fe2+ (aq)    ( True )

reason : above 3rd reason

5)   The chromium half-reaction takes place in a neutral solution.( False)

reason : reaction taking place in acidic medium

6)   The highest oxidation state for oxygen in this reaction is 0. ( False)

reason : in reactants and product oxygen oxidation state = -2

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