Questions

Natural gas is primarily composed of methane, but also contains ethane, propane, and heavier hydrocarbons.

Natural gas is a colorless, tasteless, odorless, and non-toxic gas. Because it is odorless, mercaptan is added to the natural gas, in very small amounts to give the gas a distinctive smell of rotten eggs. This strong smell can alert you of a potential gas leak.

It also contains small amounts of nitrogen, carbon dioxide, hydrogen sulphide and trace amounts of water.

Coagulation :: The action or process of a liquid, especially blood, changing to a solid or semi-solid state.

It is Blackboard or Chalkboard which is Black when clean, and as you write on it with white chalk it becomes dirty in White color.