Question

Which of the following substances is used in refining of petroleum ?

• A. $\mathrm{NaCl}$
• B. $\mathrm{NaOH}$
• C. ${\mathrm{Na}}_2{\mathrm{CO}}_3$
• D. ${\mathrm{NaHCO}}_3$

Answer 1

The correct option is B

$\mathrm{NaOH}$

Step 1: Definition of Petroleum and refining:

Petroleum is a naturally obtained oil that is made up of hydrocarbons and some other elements like Sulphur ($\mathrm{S}$), Oxygen ($\mathrm{O}$), and Nitrogen ($\mathrm{N}$). The unrefined part of petroleum is determined as crude oil. The technique of separation of various components of petroleum is termed as refining of petroleum.

Step 2: Cause of refining:

As the crude form of petroleum contains various unwanted materials such as water, salt, and small rocks, it cannot be used in this form as a fuel. Thus, refining crude petroleum is necessary.

Step 3: Method of refining:

The process of removal of sulphur content in petroleum is achieved by sodium hydroxide ($\mathrm{NaOH}$). It is known as a caustic wash in which sulphur compounds are eliminated from petroleum products.

Final answer:

Hence, option (B) is correct.