Question

Dissolution of salt in water is a _ _ _ _ _ _ _ _ change.

Answer 1

Hint: If we dissolve a salt in water, the salt will dissociate into its constituent ions which means that some new substance is being formed. It is an irreversible process and there will be either change in temperature, energy, evolution of gas or precipitate formation.


Complete step by step answer:
-We all know that any chemical change will require a chemical reaction. When a chemical compound combines with another compound to form a new compound, a chemical change occurs and is known as chemical synthesis. If it breaks into two or more substances it is known as chemical decomposition. These chemical reactions are usually not reversible but have the ability to undergo more chemical reactions further.
Those chemical reactions which require heat energy to occur are endothermic in nature and those which produce heat energy are exothermic in nature.
So, basically when a chemical reaction occurs, there is rearrangement of atoms and energy change as the products are formed.
-When we dissolve a salt in water it dissociates into its component ions. For example: Sodium Chloride (NaCl) dissociates into $N{a}^{+}$ ions and $C{l}^{-}$ ions. This can be represented as:
$NaCl(s)\to N{a}^{+}(aq)+C{l}^{-}(aq)$
Here we see that the products are different from the reactants and so a chemical change has occurred. Thus we can say that any ionic compound which is soluble in water would experience a chemical change.
Chemical changes are detected by noticing any change in colour, odour, temperature or energy, precipitate formation, gases evolved, etc.
But this is not the case with covalent compounds. When a covalent compound is dissolved in water there is no chemical change, like with sugars. When we dissolve sugar in water, the molecules get dispersed throughout the water, but there is no change in its chemical identity.


Hence as a conclusion we can say that: Dissolution of salt in water is a chemical change.


Note: A chemical change is a type of permanent change and there is change of both physical and chemical properties of the compound. Burning of coal, digestion of food and rusting are also some examples of chemical changes. But if the molecules are rearranged even though the composition remains same then the change is physical and not chemical.