Question

Find the element that produced acidic oxide
A. ${\text{Na}}$
B. ${\text{C}}$
C. ${\text{Ca}}$
D. ${\text{H}}$

Answer 1

Acidic oxides are formed by non-metals. The non-metal oxide on dissolving in water produces acid, so the non-metal oxides are acidic oxide.

Complete step by step answer:
The non-metal oxide reacts with water to give acid so the non-metal oxides are acidic oxide.
The metal oxide reacts with water to give base so the metal oxides are basic.
The elements present on the left side of the periodic table are metal and the elements present on the right side of the periodic table are non-metal.
Sodium is metal, the carbon is a non-metal, calcium is a metal, and the hydrogen is non-metal.
The oxide of sodium is ${\text{N}}{{\text{a}}_2}{\text{O}}$. The reaction of sodium oxide with water is as follows:
${\text{N}}{{\text{a}}_2}{\text{O}}\,{\text{ + }}\,{{\text{H}}_2}{\text{O}} \to \,{\text{2 NaOH}}$
The product is sodium hydroxide.
The sodium is a base and the product of hydrolysis of sodium oxide is a base, so the sodium oxide is basic hence option (A) is incorrect.
The oxide of carbon is ${\text{C}}{{\text{O}}_2}$. The reaction of carbon dioxide with water is as follows:
${\text{C}}{{\text{O}}_{\text{2}}}\,{\text{ + }}\,{{\text{H}}_2}{\text{O}} \to \,{{\text{H}}_2}{\text{C}}{{\text{O}}_3}$
The product is carbonic acid.
The carbon is non-metal and the product of hydrolysis of carbon dioxide is an acid so the carbon dioxide is acidic hence option (B) is correct.
The oxide of calcium is ${\text{CaO}}$. The reaction of calcium oxide with water is as follows:
${\text{CaO}}\,{\text{ + }}\,{{\text{H}}_2}{\text{O}} \to \,{\text{Ca}}{\left( {{\text{OH}}} \right)_{\text{2}}}$
The product is calcium hydroxide.
The calcium is a metal and the product of the hydrolysis of calcium oxide is a base, so the calcium oxide is basic hence option (C) is incorrect.
The oxide of hydrogen is ${{\text{H}}_2}{\text{O}}$. The water ionizes as follows:
${{\text{H}}_2}{\text{O}} \to \,{{\text{H}}^{\text{ + }}}\, + \,{\text{O}}{{\text{H}}^ - }$
The water produces both the ions, hydronium ion, and hydroxide ions in an equal amount, so the oxide of hydrogen or water is neutral hence option (D) is incorrect.

Therefore, Option B is correct.

Note:
The non-metal oxide reacts with a base to give salt and water that also indicates that the non-metal oxides are acidic because an acid always reacts with a base. According to Arrhenius, the acid produces hydronium ion in water whereas the base produces hydroxide ion in water so, the water is neutral because it produces both. The acidity or basicity of water depends upon the substance dissolved in it.