Structural isomers are compounds having the same molecular formula but different structures. They differ in the way the atoms are bonded to each other in the molecule. This means that they have different physical and chemical properties.

Explanation:

Molecular formula: The molecular formula of a compound gives the number of atoms of each element in one molecule of the compound. For example, the molecular formula of ethanol is C2H5OH.

Structural isomers: Structural isomers are compounds that have the same molecular formula but different structural formulas. This means that the atoms are arranged differently in the molecule.

Examples of structural isomers:

1. Butane and isobutane: Both have the molecular formula C4H10. Butane has a straight chain structure, while isobutane has a branched structure.

2. Ethanol and dimethyl ether: Both have the molecular formula C2H6O. Ethanol has a hydroxyl group attached to a carbon atom, while dimethyl ether has an oxygen atom bonded to two carbon atoms.

Physical and chemical properties: Structural isomers have different physical and chemical properties due to the differences in their structures. For example, butane is a gas at room temperature, while isobutane is a liquid. Ethanol has a higher boiling point than dimethyl ether due to the presence of a hydroxyl group, which allows it to form hydrogen bonds.

Importance of structural isomers: Structural isomers are important in many fields, such as biochemistry, pharmacology, and materials science. They can have different biological activities, such as different effects on enzymes or receptors in the body. They can also have different physical properties, such as different melting points or solubilities, which can determine their usefulness in different applications.

Different compound having same molecular formula but different structure are structural isomer it means isomer which differ in connectivity of atoms. AS- chain isomers ; position isomers ; ring chain isomer ; metamers ; functional isomers;etc