Question

Which of the following are basic oxides?

$Mn_{2}O_{7},V_{2}O_{3},V_{2}O_{5},CrO,Cr_{2}O_{3}$

• A. $Mn_{2}O_{7}$ and $V_{2}O_{3}$
• B. $V_{2}O_{3}$ and CrO
• C. CrO and $Cr_{2}O_{3}$
• D. $V_{2}O_{5}$ and $V_{2}O_{3}$

Answer 1

Answer: (B)

$V_{2}O_{3}$ and CrO

Answer 2

In case of transition metal oxides, the oxides with metals in lower oxidation states are basic in nature.

O.S. of Mn in $Mn_{2}O_{7} = + 7;VinV_{2}O_{3} = + 3;V$in $V_{2}O_{5}$ = +5; cr in CrO $= + 2;CrinCr_{2}O_{3} = + 3$

Thus in$V_{2}O_{3},$ CrO and $Cr_{2}O_{3} = + 3$ thus in $V_{2}O_{3}$ CrO and $Cr_{2}O_{3}$is amphoteric in nature hence $V_{2}O_{3}$ and CrO are basic in nature