Electrochemical Cells

For a spontaneous celll reaction, should be negative and should be positive. Hence, should be negative.

Concept: Chemistry (Electrochemistry) - Nernst Equation.

Step 1: Identify the half-cell reactions. From the given cell notation , we can write the half-reactions. At the anode (oxidation): . At the cathode (reduction): .

Step 2: Determine the overall reaction and number of electrons transferred. Combining the half-reactions gives the overall cell reaction: . The number of moles of electrons transferred in this balanced reaction is .

Step 3: State the standard Nernst equation. The Nernst equation for a cell potential at (298 K) is given by: , where is the reaction quotient.

Step 4: Formulate the reaction quotient . The reaction quotient is the ratio of the concentrations of the aqueous products to the aqueous reactants. Solid concentrations are taken as unity. .

Step 5: Substitute values into the Nernst equation. Substitute and into the equation: . Simplifying the fraction gives . The final expression is . This perfectly matches option A. $ $

Step 1: In a voltaic cell, chemical energy changes into electrical energy.

Step 2: Anode is negative electrode.

Step 3: Cathode is positive electrode.

Step 4: Dry cell is a common example of voltaic cell.

Step 5: Hence statement (C) is false. $ $