Which of the following elements forms an acidic oxide?

With the help of the following reactions,arrange metals $A$,$B$,$D$,and $E$ in decreasing order of their reactivity:
$(I)$ $B + ANO_3 \to BNO_3 + A$
$(II)$ $A + HCl \to ACl + \frac{1}{2}H_2$
$(III)$ $D + ECl \to DCl + E$
$(IV)$ $D + HNO_3 \to H_2$ gas is not evolved

Which of the following is the strongest acid?

Which of the following is/are amphoteric oxide$(s)$?

Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides?

Which of the following elements is a metalloid?