Question

Which of the following is a basic oxide?
(A).$CaO$
(B).$C{O_2}$
(C). ${H_2}O$
(D)${N_2}O$

Answer 1

Basic oxide i.s generally the oxides of metallic elements. These are called basic oxide because they give a base when treated with water.

Complete step by step answer:
As we know that there are four types of oxides acidic oxide, basic oxide, amphoteric oxide and neutral oxide
(1). Acidic oxide:- The oxides which when traded with water gives off an acid are known as acidic oxide. Generally non-metal or transition elements react with oxygen to farm acidic oxides.
(2). Basic oxide:- The oxides which when treated with water gives off a base are known as basic oxide. Car elements/metals of group 1,2 and lanthanides form basic compounds when reacted with oxygen. These compounds are generally ionic in nature. Eg :- $N{a_2}O$,$CaO$,etc.
(3). Amphoteric oxide:- These oxide are the compounds of oxygen which can show both acidic and basic nature. Eg $A{l_2}{O_3}$,${H_2}O$, etc.
(4). Neutral oxide:- These are the oxide which neither show acidic nor basic nature are known as neutral oxide. Eg $NO$,$CO$.
As we know that carbon (C) and nitrogen (N) both are the nonmetals. Thus their oxides show properties of acidic oxide. Thus $C{O_2}$ and ${N_2}O$ are acidic oxide moreover we know that ${H_2}O$ is an amphoteric oxide as it can show both acidic and basic behaviour. Calcium $\left( {Ca} \right)$ is an alkaline earth metal and only its oxide $CaO$ is basic oxide.
Hence the correct option is A.

Note:
Basic oxides are mainly ionic in nature due to high electronegative difference between the elements. Dissolving basic oxide in water can increase $PH$(basicity) of water because oxide releases $O{H^ - }$ to the water.