Which of the following is the correct order of acidic strength for $Al_2O_3$,$SiO_2$,$P_2O_3$,and $SO_2$?

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

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

Which block elements in the modern periodic table are the least electropositive?

Show by a chemical reaction with water that $Na_{2}O$ is a basic oxide and $Cl_{2}O_{7}$ is an acidic oxide.

Which of the following is the strongest acid?