The mass of carbon anode consumed (giving only carbondioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is : (Atomic mass Al = 27)

To determine the mass of carbon anode consumed, we need to analyze the reaction involved in the Hall process. The Hall process involves the electrolysis of alumina (Al2O3) to produce aluminum metal. The reaction at the anode is: $2O^{2-}\to O_2+4e^{-}$. The reaction at the cathode is: $A{l}^{3+}+3e^{-}\to Al$. Since the carbon anode is consumed, we need to consider the reaction: $C+O_2\to C{O}_2$. So, let's calculate the mass of carbon anode consumed. We know that 270 kg of aluminum metal is produced, and the atomic mass of aluminum is 27. We can calculate the number of moles of aluminum produced: $moles=\frac{mass}{atomicmass}=\frac{270}{27}=10$. Since the reaction at the cathode involves the reduction of Al3+ to Al, we can calculate the number of moles of electrons transferred: $molesofelectrons=3\times molesofAl=3\times 10=30$. Since the reaction at the anode involves the oxidation of O2- to O2, we can calculate the number of moles of O2 produced: $molesof{O}_2=\frac{molesofelectrons}{4}=\frac{30}{4}=7.5$. Since the reaction involving the carbon anode is: $C+O_2\to C{O}_2$, we can calculate the number of moles of carbon consumed: $molesofC=molesof{O}_2=7.5$. Finally, we can calculate the mass of carbon anode consumed: $massofC=molesofC\times atomicmassofC=7.5\times 12=90$. Therefore, the mass of carbon anode consumed is 90 kg.