Question

# Which is not true for a standard hydrogen electrode?A.It can act both as a cathode and anode.B.The temperature is 273K.C.The pressure is 0 atm.D.It contains a metallic conductor which does not absorb hydrogen.

Hint: 'SHE' refers to the standard hydrogen electrode.
It is a platinum electrode dipped in 1 M solution of ${ H }^{ + }$ ion (1 M HCl) at ${ 298 K }$ and hydrogen gas bubbled at 1 atm pressure. It acts as a reference electrode to find out the potential of the other half cell.

Standard hydrogen anode which is called SHE which comprises a Platinum terminal secured with a platinum black covering. This platinum terminal is dipped in a 1M arrangement of ${ H }^{ + }$ particles( generally in HCl). Hydrogen gas is gone through it at 298K and at 1 atmospheric pressure is kept up in it. Hydrogen atoms are adsorbed on the Pt terminal and carry on as a ${ H }_{ 2 }$ plate. So it has a platinum metallic channel and absorbs hydrogen gas.
It is difficult to maintain the pressure of ${ H }_{ 2 }$ gas of 1 atm throughout and also the concentration of ${ H }^{ + }$ ion of 1 M.
Note: The possibility to make a mistake is that you may not choose option B. But the temperature required in Standard Hydrogen Electrode is ${ 25 }^{ \circ }{ C }$ or ${ 298K }$ not at ${ 273K }$.