The standard emf value of some elements are listed below at 298 K. Whi

1.	The standard emf value of some elements are listed below at 298 K. Which of the following two electrodes should be combined to form a cell having highest emf ? Identify the cathode and anode and write the cell reaction. Also mention the direction of flow of electrons in the external and internal circuit.[Given E°(A2+/A) = -0.76V E°(B2+/B) = -0.44 and E°(C2+/C) = +0.34V]
Answer» For maximum emf anode should have minimum reduction potential and cathode should have maximum reduction potential. Hence A²⁺/A couple should be anode and C²⁺/C couple acts as cathode. Cell reaction A + C²⁺ → A²⁺ + C Direction of flow of electrons is from A to C in external and from C to A internal circuit. Direction of flow of current is opposite to the direction of flow of electrons.

The standard emf value of some elements are listed below at 298 K. Which of the following two electrodes should be combined to form a cell having highest emf ? Identify the cathode and anode and write the cell reaction. Also mention the direction of flow of electrons in the external and internal circuit.[Given E°(A2+/A) = -0.76V E°(B2+/B) = -0.44 and E°(C2+/C) = +0.34V]

Answer»

For maximum emf anode should have minimum reduction potential and cathode should have maximum reduction potential. Hence A²⁺/A couple should be anode and C²⁺/C couple acts as cathode.

Cell reaction A + C²⁺ → A²⁺ + C

Direction of flow of electrons is from A to C in external and from C to A internal circuit. Direction of flow of current is opposite to the direction of flow of electrons.

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