1. The electrode reaction is
Ca2+(aq) + 2e- → Ca(s)
Electricity required to produce 40 g Ca = 2 F
Electricity required to produce 20 g Ca = 1 F
2. The electrode reaction is
Al3+(aq) + 3e- → Al(s)
Electricity required to produce 27 g of Al = 3 F
Electricity required to produce 40 g Al = \(\frac{3F\times 40}{27}\)
= 4.44 F