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Question
Draw a neat and well labelled diagram of Standard Hydrogen Electrode. Also write its one application.
Solution
Standard hydrogen electrode
Application of Standard Hydrogen Electrode (SHE):
SHE is used as a primary reference electrode to determine the standard potentials of other electrodes.
e.g. To determine the standard potential of Zn2+ (1 M) | Zn(s) electrode, it is combined with SHE to a galvanic cell.
Zn(s) | Zn2+ (1 M) || H+ (1 M) | H2(g, 1atm) |Pt
The standard cell potential, `"E"_"cell"^circ`, is measured.
`"E"_"cell"^circ = "E"_("H"_2)^circ - "E"_"Zn"^circ = - "E"_"Zn"^circ`, because `"E"_("H"_2)^circ` is zero.
Thus, the measured emf of the cell is equal to standard potential of Zn2+ (1 M) | Zn(s) electrode.
RELATED QUESTIONS
Define Reference electrode
Answer the following in brief.
It is impossible to measure the potential of a single electrode. Comment.
In construction of Standard Hydrogen Electrode, platinum acts as ______.
For hydrogen gas electrode, `"E"_("H"_2)` is calculated through to Nernst equation, where `"E"_("H"_2)^0` is always _______.
Mention difficulties in settings Standard Hydrogen Electrode.
Calculate the potential of hydrogen electrode at 25°C:
Pt, H2 (1 atm) | H+ (0.1 M)
____________ is used as a primary reference electrode to determine the standard potentials of other electrodes.
Draw a neat, labelled diagram of a standard hydrogen electrode (SHE).
Write cell reaction and calculate the potential (EMF) of the cell Zn(s) | Zn2+(0.08 M) || Cr3+ (0.1 M) Cr(s) at 298 K.
\[\ce{E^0_{Zn} = - 0.76 V and E^0_Cr = - 0.74 V}\]
Write any two difficulties of setting SHE (Standard Hydrogen Electrode).
