Which of the following metals is the most reactive?

How is magnesium obtained from the following?

As compared to lithium,sodium reacts quickly with water because

Which of the following statements is incorrect?

Which of the following alloys are correctly matched with their uses?
$(i)$ $Li-Mg$ armour plates
$(ii)$ $Cu-Be$ high strength springs
$(iii)$ $Mg-Al$ aircraft construction

As per standard reduction potential values,which is the strongest reducing agent among the given elements?