Why does copper not replace hydrogen from acids?

For four metals $A, B, C$ and $D$,the standard reduction potentials are $-3.05 \ V, -1.66 \ V, -0.40 \ V$ and $0.80 \ V$ respectively. Which metal exhibits the highest chemical reactivity?

Amongst the following electrodes,the one with zero electrode potential is

The standard electrode potential for the two electrodes $A^{+}/A$ and $B^{+}/B$ are respectively $0.5 \ V$ and $0.75 \ V$. The $EMF$ of the given cell $A | A^{+}(a = 1) || B^{+}(a = 1) | B$ will be $.......... \ V$. (in $.25$)

The standard oxidation potentials of zinc and silver in water at $298 \ K$ are:
$Zn_{(s)} \to Zn^{2+}_{(aq)} + 2e^- ; E^o_{ox} = 0.76 \ V$
$Ag_{(s)} \to Ag^{+}_{(aq)} + e^- ; E^o_{ox} = -0.80 \ V$
Which of the following reactions actually takes place spontaneously?

Calculate the cell potential in volts for the cell reaction given below:
$Fe^{2+} + Zn \rightarrow Zn^{2+} + Fe$
Given:
$Zn \rightarrow Zn^{2+} + 2e^{-}, E^{0} = 0.76 \ V$
$Fe \rightarrow Fe^{2+} + 2e^{-}, E^{0} = 0.41 \ V$ (in $V$)