Why does copper not replace hydrogen from acids?

For a cell constructed with $Cu$ and $Ag$ electrodes,which of the following statements is correct regarding the cathode and the standard cell potential $(E_{cell}^{\circ})$?

Calculate the $Zn-Cu$ cell (Daniell cell) potential. Given: $E^o_{Zn^{2+}|Zn} = -0.76 \ V$ and $E^o_{Cu^{2+}|Cu} = 0.34 \ V$. (in $V$)

Consider the systems having liquid-solid interface,$(A)$ copper wire in silver nitrate solution and $(B)$ silver wire in copper sulphate solution. Predict which interface will show spontaneous reaction,if $E_{Cu^{2+}/Cu}^{\circ} = 0.34 \ V$ and $E_{Ag^{+}/Ag}^{\circ} = 0.80 \ V$?

What is the observation we get when a gold ring is placed in the solution of $AgNO_3$? $[E_{Ag^{+}|Ag}^o = 0.80 \ V$ and $E_{Au^{3+}|Au}^o = 1.40 \ V]$

Calculate the standard cell potential (in $V$) of the cell in which the following reaction takes place:
$Fe^{2+}_{(aq)} + Ag^{+}_{(aq)} \to Fe^{3+}_{(aq)} + Ag_{(s)}$
Given that:
$E^o_{Ag^{+}/Ag} = x \ V$
$E^o_{Fe^{2+}/Fe} = y \ V$
$E^o_{Fe^{3+}/Fe} = z \ V$