Answer :

Smoke comprises of very small carbon particles and tiny droplets of tar, it comprises of tiny solid particles, which has liquid and gas in it too. Smoke consists of hundreds of different chemicals, but the one we see consists of carbon, tar, oil, and ash. 

The smog, on the other hand, is a blend of smoke and fog which is also known as haze. When a large amount of coal is burned it creates a thick cloudy mixture of smoke and sulfur dioxide.

Smoke contains the gas particles which in result pollute the air but since smog is a mixture of smoke and fog so it's heavier than smoke so it causes more pollution than the smoke. 
Golda
Smoke :-

Smoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion. These are the collection of very tiny carbon particles. However smoke can contain hundreds of different chemicals and fumes. Visible smoke mostly contain carbon, tar, oil and ash. Smoke occurs when there is incomplete combustion (not enough oxygen to burn the fuel completely). When incomplete combustion occurs, not everything is burned. smoke is a collection of these tiny unburned particles. Each particle is so small to be seen with the help of our eyes, but when they come together, we see them as smoke.

Smog :-

Smog is a mixture of air pollutants. This kind of visible air pollution is composed of nitrogen dioxide, sulfur dioxide, ozone, smoke or particulates among others (less visible pollutants including carbon mono oxide and CFC). Human made smog is derived from coal emissions, vehicular emissions, industrial emissions, forest and agriculture fires and photochemical reactions of these emissions. Many parts of the world, there may be natural causes for smog. For example an erupting volcano can also emit high levels of sulfur dioxide along with a large quantity of particulate matter. Smog is a serious problem in many big cities of the world and continues to harm human health and environment.