Which of the following is used as an oxidizer in rocket propellents? (a) Liquid hydrogen (b) Nitric acid (c) Liquid hydrazine (d) Kerosene oil

Chemical oxidizers are vital components in the field of rocketry. They have a critical role of providing the necessary oxygen for fuels to combust, which is essential, especially in the vacuum of space where atmospheric oxygen is not available. Oxidizers react with rocket fuel to produce an exothermic reaction, resulting in the thrust needed to propel rockets into space.

One such example of an oxidizer is nitric acid, which is a powerful oxidizing agent used in some types of rocket propellant. Other common oxidizers include liquid oxygen (LOX), hydrogen peroxide, and nitrogen tetroxide. Each of these has its own properties and suitability for different types of missions. Nitric acid, particularly, offers the benefit of being hypergolic with certain fuels like hydrazine, meaning it ignites spontaneously upon contact without the need for a separate ignition source. This property is highly valuable for ensuring reliability and simplicity in rocket engines.

Combustion is the process of burning something. In space propulsion, this term refers to the chemical reaction between a rocket's fuel and an oxidizer to produce the high-speed expulsion of gases, which generates the thrust that propels the rocket forward. This process is known as the 'rocket equation' and is fundamental to understanding how rockets move through space.

The environment in space presents unique challenges for combustion because of the lack of atmospheric oxygen and the cold temperatures. Because of this, rocket engines must carry their own oxidizers to facilitate combustion. The design of a rocket's propulsion system must account for the ratio of fuel to oxidizer, the rate of combustion, and how the exhaust gases are expelled in order to maximize efficiency and produce the desired thrust.

Rocket fuel and oxidizers play synchronized roles in the propulsion of rockets. The fuel is the substance that burns or combusts, while the oxidizer is the substance that provides the chemical oxygen necessary for the fuel to burn. These components are carried on board in separate tanks and mixed in the combustion chamber of the rocket engine where the reaction takes place.

Fuels come in various forms, including liquid hydrogen, kerosene oil, and liquid hydrazine, each having specific energy contents and temperatures at which they can efficiently combust. Oxidizers like nitric acid enable these fuels to burn in the oxygen-deprived environment of space. The careful selection of fuel and oxidizer based on their roles and properties is essential for the success of the rocket's mission. For instance, a fuel that is hypergolic with its oxidizer can significantly simplify engine design and improve reliability. Other considerations include the temperature and pressure at which the propellants can be stored and used, as these factors also impact the overall design and execution of space missions.