The order of which of the following oxides is arranged according to decreasing basic nature?

Question

The order of which of the following oxides is arranged according to decreasing basic nature? (A) Na2O, MgO, Al2O3, CuO (B) CuO, Al2O3, MgO, Na2O (C) Al2O3, CuO, MgO, Na2O (D) CuO, MgO, Na2O, Al2O3

Tardigrade Admin · Accepted Answer

Applying Fajans’ rule, the lower the charge; the more is ionic and the more is basic and vice versa.
Moreover, small cation, large anion, high charge and presence of

d

electrons mean more covalent and more acidic.
Therefore, decreasing order of basic nature is

Size

A l^{3 +} > C u^{2 +}

and presence of d electron in

C u^{2 +}

makes it less basic (or more acidic) than

A l_{2} O_{3}

.

Q. The order of which of the following oxides is arranged according to decreasing basic nature?

$N a_{2} O$ , $M g O$ , $A l_{2} O_{3}$ , $C u O$

$C u O$ , $A l_{2} O_{3}$ , $M g O$ , $N a_{2} O$

$A l_{2} O_{3}$ , $C u O$ , $M g O$ , $N a_{2} O$

$C u O$ , $M g O$ , $N a_{2} O$ , $A l_{2} O_{3}$

Q. The order of which of the following oxides is arranged according to decreasing basic nature?

Na2​O, MgO, Al2​O3​, CuO

CuO, Al2​O3​, MgO, Na2​O

Al2​O3​, CuO, MgO, Na2​O

CuO, MgO, Na2​O, Al2​O3​

$N a_{2} O$ , $M g O$ , $A l_{2} O_{3}$ , $C u O$

$C u O$ , $A l_{2} O_{3}$ , $M g O$ , $N a_{2} O$

$A l_{2} O_{3}$ , $C u O$ , $M g O$ , $N a_{2} O$

$C u O$ , $M g O$ , $N a_{2} O$ , $A l_{2} O_{3}$