Consider the reaction: Cr2O7^2- +14 H^+ +6 e - ---> 2 Cr^3+ +7 H_2 O What is the quantity of electricity in coulombs needed to reduced 1mol of Cr_2 O_7^2- ?

Explanation

For reducing 1 mole of `Cr_2 O_7^2` ions 6 moles of electrons are required. For 1 mole of electrons .IF" or 96,500 C of electricity. is required. `therefore` For passing 6 moles of electrons or `6 ~F` of electricity is required `=6 xx 96500 C=579,000 C`