\(\begin{array}{|l|l|} \hline {\text { Dissolution of sugar }} & \text { Burning of sugar } \\ \hline \text { It forms a solution } & \text { It forms ash. } \\ \hline \text { It is a physical change } & \text { Chemical properties changed } \\ \hline \text { It will be reversible } & \text { It is irreversible } \\ \hline \text { No heat changed } & \text { Heat released } \\ \hline \end{array}\)

Yes, Desalination is a process to remove the salt from the sea water. After desalinating process we will collect water from sea.

i) Temperature variation can change the substance.
ii) Every substance has a melting point. It attain the melting temperature substance can change.

\(\begin{array}{|c|l|l|} \hline \text { S.No. } &{\text { Physical change }} &{\text { Chemical change }} \\ \hline \text { 1. } & \text { No new substance are formed } & \text { New substance are formed } \\ \hline 2 . & \text { Chemical properties do not change } & \text { Chemical properties changed } \\ \hline 3 . & \text { It is a temporary action. } & \text { It is a permanent action. } \\ \hline 4 . & \text { It is a reversible reaction } & \text { It is a irreversible reaction. } \\ \hline \end{array}\)

Iron blade is heated so that it expands and fixes on the wooden handle then it cooled. so that it contracts and firmly attaches to the handle

Digestion of a food is considered as a chemical change as various chemical reactions take place while digestion of food. More over as chemical changes are irreversible change. The food items changed into various nutrients like carbohydrate, fat and protein. So new substance are formed by evolution or obsorption of heat. So it is a chemical change.

(i) Boiling of water is a physical change because it is a reversible action. No new substance is formed.
(ii) Boiling of egg is a chemical change because it is a irreversible action and new substance are formed.

Suddenly variation of temperature it shrinks so it will be cracks. so heat is obsorbed suddenly heat liberated it indicates a exothermic reaction.

(i) Yes, it is a chemical change.
(ii) Banana fruits contain an enzyme cailed polyphenol oxidase which cause chemical reaction when exposed to oxygen. Now the peeling banana colour is changed. So it is a chemical change.