The number of moles of electron required to reduce ( 0.2 ) mole of ( Cr ₂ O ₇⁻² ) to ( Cr ⁺³ )

Step-by-step solution

[ array l (C) Cr ₂ O ₇ ⁻² 6 e⁻ 2 +3 Cr array ] ( 1 ) mol requires ( 6 ) mole of electrons ( 0.2 ) mol requires ( 0.2 6 1 =1.2 ~mol ) of electrons