Question

The standard electrode potential is measured by:
A) Electrometer
B) Voltmeter
C) Potentiometer
D) Galvanometer

Answer 1

Let us firstly define Standard electrode potential, it is the measure of the individual potential of reversible electrode at standard state with ions at an effective concentration of 1 mol $d{m^{ - 3}}$ at the pressure of 1 atm.

Complete answer:
Generally, electrode potential is the relative tendency of electronics and electrolytics for the charge cell. It is also known as half cell electromotive force (emf). We know that as the name suggests electrometer is used to measure electric charge or electric potential difference, Voltmeter is used to measure the voltage or the electric potential and Galvanometer is used for detecting and indicating an electric current.
Potentiometer is used to measure standard electrode potential and to compare the emf of two cells. Also it has the advantage that it draws no current from the voltage source being measured as it is unaffected by the internal resistance of the source. It is a versatile instrument. It is basically a long piece of uniform wire, sometimes a few meters in length across which a standard cell is connected.
One can use a potentiometer to measure the internal resistance of a cell. Emf across uniform wire of length l in potentiometer is can be depicted as
${\rm E}(l) = \Phi l$
The standard electrode potential is measured by the potentiometer. It is the potential difference when no current is flowing in the circuit.

Hence we can conclude that the correct option is C.

Note: All these devices can be converted into each other by making certain changes. For example a galvanometer can be converted into voltmeter by connecting a high resistance called multiplier in series to the galvanometer.