Mendeleev's periodic table faced several anomalies. Which of the following was one of them? MCQ with Answer and Explanation

Explanation:
Chlorofluorocarbons (CFCs), used in refrigerants and aerosols, reach the stratosphere where UV radiation breaks them down, releasing chlorine atoms. These chlorine atoms catalytically destroy ozone (O₃) molecules, leading to the depletion of the ozone layer, particularly over Antarctica.

Explanation:
Natural gas is a fossil fuel composed primarily of methane (CH4), typically making up 70-90% of its volume. It also contains smaller amounts of ethane, propane, butane, and other heavier hydrocarbons, along with non-hydrocarbon gases like carbon dioxide and nitrogen.

Explanation:
LPG (propane/butane) is odorless. A small amount of strong-smelling mercaptan (ethanethiol) is added to help detect gas leaks, preventing accidents. Natural gas also has odorant. Mercaptans contain sulfur, and their smell is detectable at very low concentrations. Calorific value, temperature, performance are unaffected. Safety is primary.