Which combination of gases is commonly used in different types of welding processes?

Introduction / Context:
Welding is a key industrial process used to join metals. Different types of welding processes, such as oxy fuel welding and arc welding, use various gases either as fuel, oxidisers, or shielding gases. General science and technical aptitude questions often ask about common gas combinations used in welding, especially the classic oxygen acetylene combination and shielding gases like argon.

Given Data / Assumptions:

• The question asks about gases used in different types of welding.
• Options provide several combinations involving oxygen, hydrogen, acetylene, argon, and nitrogen.
• We assume common welding methods: oxy acetylene welding and arc welding processes like MIG and TIG.

Concept / Approach:
Oxy acetylene welding uses a mixture of oxygen and acetylene to produce a very hot flame for melting and joining metals. In addition, modern arc welding processes such as MIG (Metal Inert Gas) and TIG (Tungsten Inert Gas) use inert gases like argon as shielding gases to protect the molten weld from atmospheric contamination. Thus, across different welding types, oxygen, acetylene and argon are all important. Hydrogen and nitrogen are specialised or less desirable in many common welding procedures, making the combination that includes oxygen, acetylene and argon the best match to the phrase different types of welding.

Step-by-Step Solution:
Step 1: Recognise that oxygen and acetylene together form the oxy acetylene flame, widely used in gas welding and cutting. Step 2: Recall that argon is a noble gas used as a shielding gas in MIG and TIG welding to prevent oxidation and contamination. Step 3: Understand that the question mentions different types of welding, suggesting we should think beyond just one process. Step 4: Observe that the combination oxygen, acetylene and argon covers both oxy fuel welding and shielded arc welding. Step 5: Conclude that oxygen, acetylene and argon is the most appropriate answer among the given choices.

Verification / Alternative check:
Standard welding handbooks describe oxy acetylene welding as the most common gas welding process, using a combination of oxygen and acetylene. For arc welding processes, shielding gases such as argon, helium, or CO₂ are essential. Very few common processes rely primarily on nitrogen or hydrogen as core welding gases; nitrogen can even cause porosity and brittleness in some welds. Therefore, a combination that includes oxygen, acetylene and argon correctly reflects gases used across multiple welding methods.

Why Other Options Are Wrong:
Oxygen and hydrogen: This combination can produce a flame but is not the standard for common welding due to safety and material concerns. Oxygen and acetylene: Correct for oxy acetylene welding alone but does not reflect gases used in other common welding types such as MIG or TIG. Oxygen, hydrogen, acetylene and nitrogen: Includes gases not typically desirable as general welding gases; nitrogen is not a standard shielding gas. None of the above: Incorrect because oxygen, acetylene and argon together accurately represent gases used in multiple welding processes.

Common Pitfalls:
Many students immediately choose oxygen and acetylene because it is the most famous pair and forget that the question refers to different types of welding, not just oxy fuel. Others might be confused by the presence of nitrogen and hydrogen, thinking more gases must be better. To avoid such mistakes, remember that argon is a key shielding gas in arc welding, and combining oxygen, acetylene and argon covers both major categories: gas welding and arc welding.

Final Answer:
The gases commonly used across different welding processes include oxygen, acetylene and argon.