Alkynes are less reactive than alkenes towards electrophilic reagents. But the alkyne chemistry is useful for organic synthesis, in the form of hydration of the triple bond, formation of metalacetylides, selective reduction of alkynes and few other related reactions.

Question: Compare the reactivity of alkynes to alkenes and explain how this affects their use in organic synthesis, including examples of reactions. Answer: Alkynes are less reactive than alkenes due to their higher electronegativity, smaller bond angle, and delocalization of π-bonds, all of which contribute to their stability. Despite this lower reactivity, alkynes play a crucial role in organic synthesis because they can undergo diverse reactions such as hydration of the triple bond, formation of metal acetylides, and selective reduction to either alkenes or alkanes using different catalysts. For example, they can be selectively reduced to cis-alkenes using Lindlar's catalyst or fully reduced to alkanes with a Pt or Pd catalyst.