Explanation:

The process that does not involve a catalyst is the Thermite process.

The Thermite process is a chemical reaction between a metal oxide and a reducing agent, typically aluminum, which results in the production of metal and oxide. This reaction is highly exothermic and is used in various applications, such as welding and incendiary devices.

Here's why the Thermite process does not involve a catalyst:

Catalyst:
A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It provides an alternative pathway for the reaction with lower activation energy, allowing the reaction to occur more readily.

Thermite Process:
The Thermite process is an example of a highly exothermic reaction that occurs spontaneously under appropriate conditions, without the need for a catalyst. The reaction between the metal oxide and reducing agent releases a large amount of heat, which is sufficient to sustain the reaction without the assistance of a catalyst.

Other Processes:
On the other hand, the Oswald process, Haber process, and Contact process all involve the use of a catalyst to facilitate the desired reactions.

- Oswald process: This process is used for the production of hydrogen gas by the reaction of water with aluminum. It involves the use of a catalyst, typically a small amount of a transition metal, to increase the rate of the reaction.

- Haber process: The Haber process is used for the synthesis of ammonia from nitrogen and hydrogen. It requires the use of an iron catalyst, which promotes the formation of ammonia by lowering the activation energy of the reaction.

- Contact process: The Contact process is used for the production of sulfuric acid. It involves several catalytic steps, including the oxidation of sulfur dioxide to sulfur trioxide using a vanadium(V) oxide catalyst, and the conversion of sulfur trioxide to sulfuric acid using a sulfuric acid catalyst.

Therefore, the Thermite process is the only process among the options provided that does not require a catalyst for its reaction to occur.