10. Biomolecules — Chemistry STD 12 Science — Question

$(I)$ $ZnCl_2$ is ionic whereas $CdCl_2$ and $HgCl_2$ are covalent

$(II)$ $Zn$ and $Cd$ dissolves in dilute acid $(HCl)$ liberating $H_2$ but $Hg$ can not

$(III)$ $Zn$ and $Cd$ forming with ppt. of $Zn(OH)_2$ and $Cd(OH)_2$ but $Hg$ forms coloured ppt. of

$(IV)$ all from $A_2^{2+}$ type ion

$Cu^{+2} + 2e^-\to Cu$ ; $E^o = X_2$ then the value of $E^o$ for $Cu^{+2} + e^-\to Cu^+$ will be