Question

Question:
Which of the following is used as rocket fuel?
(A) \[{F_2}\]
(B) \[{N_2}\]
(C) \[{C_2}{H_2}\]
(D) \[C{H_4}\]

Answer 1

Hint: Two kinds of fuels are used in rockets: liquid fuel and solid fuel. As there is no atmosphere in space, rockets need to carry both their own fuel and oxidizers to burn the fuel. Oxidizers should be reactive to perform explosive reactions.

Complete step-by-step solution:
A branch of aerospace engineering, called rocket science is based on Newton’s law of motion. There are two primary fuels used in the rocket.
Liquid fuel: this is the most common one and includes fuel and an oxidizer. These provide more energy than solid propellants, but liquids are difficult to store and are costly too. For example, kerosene, hydrazine, liquid hydrogen as fuel and liquid oxygen, liquid fluorine, nitric acid as oxidizers.
Solid fuel: due to their lack of control and efficiency, these are less preferred. They also have fuel with oxidizer but in solid state. These are cheap and easy to store. For example, aluminium as fuel and ammonium perchlorate as oxidizer.
Both the fuel and oxidizer are burnt in the combustion chamber resulting in the expansion of the gases. The rocket moves forward by the pressure in the gas that hits harder on the top. From the bottom, the exhaust is released due to low pressure there. Fluorine being highly reactive of all the elements, shortens the timing needed for ignition and increases the rate of combustion.

Hence, the correct option is (A).

Note: To fly a rocket, both solid and liquid fuels are required. Although liquid fuel is more efficient yet its storage requires huge tanks. Therefore, rockets use solid fuel to boost off the ground, this makes it lighter and then the liquid fuel is ignited to allow the rocket to keep moving upward in space.