Question

which of the following oxides dissolve in water to give a alkali solution ?
SO2 CaO SO3 NO2
with explanation

Answer 1

An acidic solution can be formed when a non-metal oxide is dissolved in water. For example, magnesium oxide dissolves to form alkaline solutions. Sulfur dioxide and nitrogen dioxide however, will dissolve to form acidic solutions.

Answer 2

CaO (Calcium oxide) dissolves in water to give an alkali solution.

Reason - CaO dissolves in water to give $Ca(OH)_{2}$  as it is a basic oxide.

What are Basic oxides?

• Oxides which reacts with water to form base are called basic oxides.
• In other words, Metals which react with oxygen to form basic compounds of oxygen are called basic oxides.
• These compounds are generally ionic in nature.
• Example - MgO, CaO, $Na_{2} O$