Question

Classify the following as physical properties or chemical properties:
Most metal oxides form alkali on interacting with water.
(a)- Chemical property
(b)- Physical property
(c)- Both (a) and (b)
(d)- None of these

Answer 1

If there is a change in the physical form of the compound or which only tells the physical form of the compound is known as the physical property like size, color, melting point, boiling point, solubility, etc. If there is a change in the composition of the compound or in which the reactant changes to the product is the chemical property.

Complete step by step answer:
-Two types of properties can define the property of the compound: these are physical property and chemical property.
-If there is a change in the physical form of the compound or which only tells the physical form of the compound is known as the physical property like size, color, melting point, boiling point, solubility, etc.
-If there is a change in the composition of the compound or in which the reactant changes to the product is the chemical property, like the reaction of the compound with acids, water, oxygen, halogens, carbon dioxide, etc.
-When the metal oxide reacts with water there is the formation of alkali, so in metal oxide, there are two elements metal and oxygen and in alkali, there are metal and hydroxyl ions, this means that the composition has changed or we can say that the reactant has changed to the product. Hence this is a chemical property of metal oxides.

Therefore, the correct answer is an option (a)- Chemical property.

Note: An example of a metal oxide that converts to alkali when it reacts with water is sodium oxide: it reacts with water to form sodium hydroxide. The reaction is given below:
$N{{a}_{2}}O+{{H}_{2}}O\to 2NaOH$