Which of the following is a saturated carbon compound? MCQ with Answer and Explanation

Explanation:
An amalgam is an alloy of mercury with another metal. For example, sodium amalgam (used as reducing agent), zinc amalgam (for Clemmensen reduction), and dental amalgam (mercury-silver-tin-copper). Most metals dissolve in mercury, forming amalgams, except iron and platinum. Amalgams can be liquid or solid depending on proportion. Used in gold extraction.

Explanation:
A positive catalyst increases reaction rate by lowering activation energy. Decreasing temperature generally slows reactions. Decreasing concentration reduces collision frequency, lowering rate. Larger pieces have less surface area, slower reaction. Other rate-increasing factors: increasing temperature, increasing pressure (for gases), using finely powdered solids, and light for photochemical reactions.

Explanation:
CNG (methane) has a higher H/C ratio, so combustion produces less CO₂ per unit energy compared to petrol/diesel. It also burns completely without generating smoke or particulate matter, and contains no sulfur, thus no SO₂. It reduces NOx and unburned hydrocarbons. It is used in vehicles and is safer in spills because it is lighter than air and disperses quickly.