solve 29.
The   charge   required   for   the   reduction   of   1   mol   of   Cr 2 O 7 2 -   to   Cr 3 +   is a ) 96500   C b )   1 . 93 × 10 5 C c )   5 . 79 × 10 5 C d )   2 . 895 × 10 5 C
 

Dear Student,
The change can be shown as

Cr2O72-Cr3+
Cr changes from +6 to+3 hence there is a change of 3e​-
charge = n×F
so charge = 3F
we know 1F=96500
so charge needed = 289500 or 2.98×105C
hence correct option is (d)
Regards!

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