An alkene and an alkyne are both unsaturated hydrocarbons, meaning they contain carbon-carbon double or triple bonds, respectively. They differ in their chemical structure, physical properties, and reactivity, which in turn affects their applications in various industries.Chemical Structure:1. Alkenes: Alkenes have a carbon-carbon double bond C=C in their structure. The general formula for an alkene is CnH2n, where n is the number of carbon atoms. Examples of alkenes include ethene C2H4 , propene C3H6 , and butene C4H8 .2. Alkynes: Alkynes have a carbon-carbon triple bond CC in their structure. The general formula for an alkyne is CnH2n-2, where n is the number of carbon atoms. Examples of alkynes include ethyne C2H2, also known as acetylene , propyne C3H4 , and butyne C4H6 .Physical Properties:1. Alkenes: Alkenes are generally less dense than water and have relatively low boiling and melting points. Their boiling points increase with increasing molecular weight. They are insoluble in water but soluble in organic solvents.2. Alkynes: Alkynes also have low boiling and melting points, with boiling points slightly higher than those of corresponding alkenes. Like alkenes, they are insoluble in water but soluble in organic solvents.Reactivity:1. Alkenes: Alkenes are more reactive than alkanes due to the presence of the carbon-carbon double bond. They undergo addition reactions, such as hydrogenation, halogenation, and hydration, where the double bond is broken, and new atoms or groups are added to the carbons. Alkenes can also participate in polymerization reactions, forming long-chain polymers.2. Alkynes: Alkynes are even more reactive than alkenes due to the presence of the carbon-carbon triple bond. They undergo similar addition reactions as alkenes, but they can also undergo reduction reactions to form alkenes or alkanes. Additionally, alkynes can participate in coupling reactions, where two alkynes combine to form a larger molecule.Industrial Applications:1. Alkenes: Alkenes have a wide range of applications in the chemical industry. They are used as starting materials for the production of polymers, such as polyethylene and polypropylene. They are also used in the synthesis of various chemicals, such as alcohols, detergents, and plasticizers. Ethene, for example, is used to produce polyethylene, which is widely used in packaging materials, pipes, and other plastic products.2. Alkynes: Alkynes have more specialized applications due to their higher reactivity. Acetylene ethyne is used in welding and cutting metals, as it produces a very high temperature flame when burned with oxygen. It is also used as a starting material for the synthesis of various chemicals, such as acetic acid and vinyl chloride. Other alkynes are used in the synthesis of pharmaceuticals, fragrances, and specialty chemicals.In summary, alkenes and alkynes differ in their chemical structure, physical properties, and reactivity, which influences their applications in various industries. Alkenes are widely used in the production of polymers and chemicals, while alkynes have more specialized uses, such as metal welding and the synthesis of specialty chemicals.