How do chromium metal, and Pb2+ interact electrochemically?

1 Answer
Sep 9, 2015

Chromium metal is oxidized to Cr3+, and lead is reduced from Pb2+ to Pb0. Half equations follow.

Explanation:

Oxidation half equation:

CrCr3++3e(i)

Reduction half equation:

Pb(NO3)2+2ePb0+2NO3 (ii)

Both equations are balanced with respect to mass, and to charge. The overall equation is simply the sum of equations (i) and (ii) such that electrons do not appear in the final reaction: i.e. 2×(i)+3×(ii):

2Cr+3Pb(NO3)22Cr3++3Pb0+6NO3.

Note that the overall redox equation is balanced with respect to mass and charge, as indeed it must be.