An alloy which does not contain copper is

For a good quality cement,the ratio of lime to the total of the oxides of $Si$,$Al$ and $Fe$ should be as close as to :

$II-A$ (alkaline earth metals) and $II-B$ (zinc family) resemble in which of the following properties?

Which of the following statements are false?

Which orders are correct?
$(I)$ Thermal stability: $BeSO_4 < MgSO_4 < CaSO_4 < SrSO_4$
$(II)$ Basic nature: $CaO > MgO > BeO > ZnO$
$(III)$ Solubility in water: $LiOH < NaOH < KOH < RbOH$
$(IV)$ Melting point: $NaCl > KCl > RbCl > CsCl > LiCl$

Copper becomes green when exposed to moist air for a long period. This is due to