To calculate the efficiency of the voltaic cell, we need to determine the actual work done by the cell and compare it to the theoretical maximum work that could be done.First, let's find the actual work done by the cell. Work is equal to the charge Q multiplied by the potential difference V :Actual work = Q VActual work = 2400 C 0.78 VActual work = 1872 JoulesNext, let's find the theoretical maximum work that could be done. We know that the cell produces a current of 2.5 A and operates for 8 hours. First, we need to convert the time to seconds:8 hours 3600 seconds/hour = 28800 secondsNow, we can find the total charge that could be produced by the cell:Q_theoretical = Current TimeQ_theoretical = 2.5 A 28800 sQ_theoretical = 72000 CoulombsThe theoretical maximum work is then:Theoretical work = Q_theoretical VTheoretical work = 72000 C 0.78 VTheoretical work = 56160 JoulesNow we can calculate the efficiency of the cell:Efficiency = Actual work / Theoretical work 100%Efficiency = 1872 J / 56160 J 100%Efficiency 3.33%The efficiency of this electrochemical cell is approximately 3.33%.