Answer the question on basis of passage given below:
The noble gases have closed shell electronic configuration and are monatomic gases under normal conditions. The low boiling points of lighter noble gases are due to the weak dispersion forces between the atoms and the absence of other inter atomic interaction. The direct reaction of xenon with fluorine leads to a series of compounds with oxidation numbers +2, +4 and +6.
\(XeF_4\) reacts violently with water to give \(XeO_3\). The geometries of the compounds of xenon can be deduced considering the total number of electrons in the valence shell.
Argon is used in arc welding because it has
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Lower reactivity with metals
In arc welding the metal is melted at a very high temperature, where it would quickly react with the oxygen and nitrogen of the air. Argon is a noble gas with a closed-shell configuration and is almost inert; it does not react with the hot metal. A blanket of argon keeps air away from the weld and gives an inert atmosphere for the high-temperature process.
Why the other options are incorrect
Option (2) Ability to lower the melting point of the solid — Incorrect. Argon does not dissolve in or alloy with the metal, so it does not change its melting point.
Option (3) Flammability — Incorrect. Argon does not burn; a flammable gas would be dangerous at the welding arc.
Option (4) High calorific value — Incorrect. Calorific value is the heat a fuel gives when it burns; argon does not burn and supplies no heat.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Uses
