Physics · Internal resistance, potential difference and emf of a cell, a combination of cells in series and parallel

A cell constructed by coupling a standard copper electrode and a standard magnes

A cell constructed by coupling a standard copper electrode and a standard magnesium electrode has emf of 2.7 volts. If the standard reduction potential of the copper electrode is +0.34 volt, that of magnesium electrode is:

  • A. +3.04 volts
  • B. -3.04 volts
  • C. +2.36 volts
  • D. -2.36 volts

Step-by-step solution

The cell emf (2.7 V) equals the reduction potential of the cathode (copper, +0.34 V) minus that of the anode (magnesium). Thus, 2.7 = 0.34 - E_Mg, solving gives E_Mg = -2.36 V.
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