Explain the terms substitution and addition reactions? Methane gives substitution reaction while ethylene gives addition reaction. Justify the statement giving two examples in each case.

Explain the following :

Friedel-Crafts acylation

Explain the following : 

Kolbe’s electrolytic method.

If one mole of $\mathrm{HBr}$ is added to the following compounds, write down the structures of the product/products expected to the formed.

Buta-1, 3-diene

If one mole of $\mathrm{HBr}$ is added to the following compounds, write down the structures of the product/products expected to the formed.

Penta-1, 3-diene

If one mole of $\mathrm{HBr}$ is added to the following compounds, write down the structures of the product/products expected to the formed.

Penta-1, 2-diene

If one mole of $\mathrm{HBr}$ is added to the following compounds, write down the structures of the product/products expected to the formed:

Hept-1-ene.