Question

Crude oil is a complex mixture of:
A.Solid hydrocarbons
B.Liquid hydrocarbons
C.Gaseous hydrocarbons
D.All of these

Answer 1

To answer this question, you should recall the concept of the formation of fossil fuels. Petroleum is a fossil fuel derived from ancient fossilized organic materials, such as zooplankton and algae. Vast amounts of these remains settled to sea or lake bottoms where they were covered in stagnant water or sediments such as mud and silt.

Complete answer:
We know that fossil fuel is used to refer to buried combustible organic deposits, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust.
With an increase in depth settling of multiple layers, there is a buildup of intense heat and pressure. Due to this the organic matter first turns into a waxy material known as kerogen and then changes with more heat to turn into liquid and gaseous hydrocarbons via a process known as catagenesis.
Petroleum is composed primarily of hydrocarbons, although hydrocarbon derivatives containing oxygen, nitrogen, or sulfur are also present.
Additionally, some metals are present at trace levels. Although the composition of crude oil varies from location to location, and even within a single well, the basic elemental composition of crude oil shows little variation from one source to another.

Thus, Option D is correct.

Note:
For the formation of petrol there is a particular window of temperature that the zooplankton must find. If it is less than this window temperature, the oil will remain trapped in the form of kerogen, but too hot and the oil will be changed into natural gas. This ideal temperature is achieved by organic material rich deposit at an appropriate depth, a porous and permeable rock for accumulation and a sealing mechanism must be present to prevent it from escaping to the surface.