Addition reactions of alkenes and alkynes are very important in organic chemistry. They involve adding other substances to the double or triple bonds found in these compounds. Here are the main types of these reactions:

1. Electrophilic Addition:

   • In this reaction, electrophiles, which are positively charged particles, attack the electron-rich double bond. A good example is when hydrogen bromide (HBr) adds to ethylene (C₂H₄). This creates something called a carbocation intermediate.

2. Nucleophilic Addition:

   • Alkynes can also take part in nucleophilic addition. An example is when they react with lithium aluminum hydride (LiAlH₄). This reaction produces alcohols.

3. Radical Addition:

   • This type of addition happens when radical initiators are present. A good example is the bromination of alkenes, which occurs under radical conditions.

These different types of reactions show how flexible alkenes and alkynes are in making new organic compounds.