Which reference electrode is used to measure the electrode potential of other electrodes?

Why does copper not replace hydrogen from acids?

Will $Fe_{(s)}$ be oxidised to $Fe^{2+}$ by the reaction with $1 \ M$ $HCl$ ($E^o$ for $Fe/Fe^{2+} = +0.44 \ V$)?

Which of the following is the strongest oxidising agent?

Standard electrode potential for $Sn^{4+}/Sn^{2+}$ couple is $+0.15 \ V$ and that for the $Cr^{3+}/Cr$ couple is $-0.74 \ V.$ These two couples in their standard state are connected to make a cell. The cell potential will be ........ $V$

Electrode potentials of five elements $A, B, C, D$ and $E$ are respectively $-1.36 \ V, -0.32 \ V, 0 \ V, -1.26 \ V$ and $-0.42 \ V$. The reactivity order of these elements is: