Which of the following pairs represents isobars? MCQ with Answer and Explanation

Explanation:
Total electrons = 16 (Sulfur). Period = number of shells = 3. Valence electrons = 6, group = 10+6 = 16 (Group 16, chalcogens). Group 6 would be 6 valence electrons but in d-block, not applicable. Group 18 has 8 valence electrons (except He). So sulfur is in group 16, period 3.

Explanation:
Petroleum (crude oil) and natural gas are formed from the remains of tiny marine organisms (plankton) that settled on the seabed, buried under sediment, and transformed by heat and pressure over millions of years. Coal is formed from terrestrial plant material in swampy conditions. Biogas is produced by anaerobic decomposition of organic waste. Charcoal is produced by destructive distillation of wood.

Explanation:
Propane is an alkane with three carbon atoms: CH₃CH₂CH₃, formula C₃H₈. Methane: CH₄, Ethane: C₂H₆, Butane: C₄H₁₀. Propane is a component of LPG. Alkanes follow CnH₂n+2. For n=3, H=8. Propane is a gas at room temperature, liquefied under pressure. It is used as fuel for heating and cooking.