![]() Zinc half cell is taken as cathode and hydrogen half cell is taken as the anode.Īs we know, the standard reduction potential of standard hydrogen electrode is always taken as 0 in standard conditions and we are using standard conditions in the experiment. A salt bridge is also used which prevents intermixing of the solutions and maintains the electrical neutrality of the solutions. Now, this zinc electrode is connected to a standard hydrogen electrode by using a voltmeter which will measure the electrode potential of the cell. 1M concentration of electrolyte zinc sulfate is taken. For this, zinc sulfate is taken in a beaker and a zinc rod is dipped in it. This half cell of standard hydrogen electrode is connected with a half cell of zinc electrode. A figure of Standard Hydrogen Electrode is shown below. It has an inlet for pure hydrogen gas (1atm) to enter the solution. Now a platinum inert electrode with platinum black foil at one end is immersed in the beaker and a glass jacket is kept on it to prevent the entry of oxygen. The experiment is described below-Ĭonstruction of standard hydrogen electrode - To construct a standard hydrogen electrode, we take a hydrogen chloride solution of 1M in a glass beaker. Standard reduction potential and standard oxidation potential for standard hydrogen potential are always taken 0.00. We are describing here a method of calculating standard reduction potential by taking a zinc electrode in a half cell with zinc sulfate (electrolyte) against a standard hydrogen electrode. It can be represented as –Ĭalculating Standard Reduction Potential for Zinc Electrode The standard cell potential is the difference between standard reduction potentials of two half–cells or half-reactions. Either Standard reduction potential or standard oxidation potential can be calculated for an electrode using a standard hydrogen electrode. Standard electrode potential is denoted by E0. It is the base of the thermodynamic scale of oxidation-reduction potentials. Value of its standard reduction potential and standard oxidation potential is always zero at 25℃ or 298K. It can act as anode half - cell as well as cathode half-cell. It is used as a reference electrode for determination of standard electrode potential of elements and other half cells. Standard hydrogen electrode is a gas – ion electrode. ![]() It is measured with respect to standard hydrogen electrodes. Standard conditions mean temperature at 298K, pressure should be 1 atm, the concentration of the electrolyte used should be 1M. The potential of the half-reaction (half-cell) measured against the standard hydrogen electrode under standard conditions is called the standard electrode potential for that half-cell or half reaction. Cell potential is measured experimentally which is equal to the sum of potentials on the two electrodes.Įcell is measured by voltameter experimentally and electrode potential of one electrode is already known so electrode potential of another (electrode with unknown electrode potential) can be calculated. So, in an experiment to measure electrode potential, in a cell one electrode is used as a reference electrode whose potential is already known and another electrode is used of unknown potential. Only the difference in potential between two electrodes can be measured experimentally. ![]() ![]() It is not possible to measure accurately the absolute value of single electrode potential directly. In electrochemistry the electrode potential is the electromotive force of a cell built of two electrodes. According to IUPAC electrode potential has been defined as follows. ![]()
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