The physical changes can alter the form of a substance but does not necessarily change it to an other substance
Explanation:
The physical properties of matter is one that does not depend on composition.It just change the form of matter into another form with changing into composition.
Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.
The three states of matter are: solid, liquid, and gas. The melting point and boiling point are related to changes of the state of matter. All matter may exist in any of three physical states of matter.
Example:
When water is boiled then it change into vapors. Now the form of water is change but its composition is same like water
When water freezes into ice, now phase are different i.e water is liquid while ice is solid but both have same composition.
The reaction begins with a hydride nucleophile reacting with the ester carbonyl carbon to form the tetrahedral intermediate.
The carbonyl reforms to produce an aldehyde with the loss of the alkoxide ion.
The resulting aldehyde undergoes a subsequent reaction with a hydride nucleophile to form another tetrahedral intermediate. The carbonyl is not able to reform, because there are no stable leaving groups.
Therefore, the tetrahedral intermediate is protonated to produce a primary alcohol.
