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Answered

44 Given the balanced ionic equation:

3Pb2+ + 2Cr ==> 3Pb + 2Cr3+


What is the number of moles of electrons gained by 3.0 moles of lead ions?


(1) 5.0 mol (3) 3.0 mol


(2) 2.0 mol (4) 6.0mol



I Know That the answer is 4 I just need an explanation of how

Verified Answer :

meerkat18

To solve this redox equation, we divide the equation into two parts: the oxidation and the reduction part. The reduction part is 3 Pb 2+ = 3 Pb while the oxidation part is 2 Cr = 2 Cr3+. We balance the charges. 3 Pb 2+ + 6e- = 2 Pb and 2 Cr = 2 Cr 3+  + 6e-. Adding the two equations, the 6 e- just cancels out. Hence for 3 moles of lead ions, there are 6 moles of electrons gained.