When alcohol reacts with concentrated sulphuric acid, H\(_2\)SO\(_4\), it undergoes a dehydration reaction that removes water molecules. The reaction can produce alkenes or ethers, depending on the conditions. 

Concentrated sulfuric acid is a strong oxidizing agent that absorbs water. It removes the hydroxyl (OH) group from the alcohol carbon atom and a hydrogen atom from an adjacent carbon atom. 

• Alkenes: The reaction can produce alkenes, such as ethene, C\(_2\)H\(_4\), when the alcohol loses water molecules. 

• Ethers: The reaction can produce Ethers, such as diethyl ether, when two alcohol molecules are dehydrated.