Question

Which of the following processes does not involve a catalyst?
A. Haber's process
B. Thermite process
C. Ostwald process
D. Contact process

Answer 1

Hint: Catalyst is a substance that ascends the pace of a reaction and does not get used up in the process. This process is called catalysis.

Complete Step by Step Answer:
A. Haber's process
Haber’s process is the industrial production of ammonia.
$N_{2}+3H_{2}\overset{Fe}\rightleftharpoons 2NH_{3}$
The enthalpy of formation required for this reaction is -46.1 kJ/mol.
In agreement with Le Chatelier’s principle, elevated pressure is required for the formation of ammonia.
The usage of a catalyst like iron
oxide with small amounts of potassium dioxide and aluminium dioxide boosts the pace of achievement of equilibrium.
Iron was utilised as a catalyst with molybdenum as a promoter.
So, A is incorrect.

B. Thermite process
Thermite is a combination of metal oxide and metal that is organised to create a heating effect.
These compounds have a pyrotechnic arrangement.
When thermite is set on fire, it partakes in an exothermic redox reaction.
This reaction is exothermic.
The thermite combination is iron oxide $(Fe_{2}O_{3})$ reacting with aluminium to yield molten iron.
The products are aluminium oxide $(Al_{2}O_{3})$ and elemental iron with a large amount of heat.
When the mixture is heated, it begins reacting with aluminium being more reactive than iron, and it constitutes powerful and additionally stable bonds with oxygen than iron.
The chemical reaction of interest is:
$Fe_{2}O_{3}+Al\longrightarrow Al_{2}O_{3}+Fe$
This reaction is also called the Goldschmidt process.
The reaction is a redox reaction as iron undergoes reduction and aluminium undergoes oxidation.
It doesn't have to do with a catalyst as it is a fast reaction.
So, B is correct.

C. Ostwald process
It is a process used to prepare nitric oxide on an industrial scale.
On a large scale, it is prepared mainly by Ostwald’s process.
This technique is established on catalytic oxidation of ammonia by atmospheric
oxygen.
Platinum or rhodium gauze catalyst is used for this reaction.
$4NH_{3}(g)+5O_{2}(g)\overset{Pt/Rh gauze}\longrightarrow 4NO(g)+6H_{2}O(g)$
So, C is incorrect.

D. Contact process
Sulphuric acid is extensively crucial in the chemicals industry.
It is produced by the Contact Process involves three steps:
(i) Burning of sulphur or sulphide ores in the air to yield sulphur dioxide.
(ii) Transformation of sulphur dioxide to sulphur trioxide by the reaction with oxygen in the presence of a catalyst vanadium peroxide.
$2SO_{2}(g)+O_{2}(g)\overset{V_{2}O_{5}}\longrightarrow 2SO_{3}$
(iii) Absorption of sulphur trioxide in sulphuric acid to give Oleum.
So, a catalyst is also used for this reaction.
So, D is incorrect.
So, option C is correct.

Note: It must be noted that catalysts speed up a reaction. Thermite is a redox reaction that happens on its own and doesn't need a catalyst. Haber's process, Contact process, and Ostwald's process need a catalyst.