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.
Which noble gas is generally used in illuminating warning signals?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Neon
When an electric discharge is passed through neon at low pressure, it glows with a bright orange-red light that can be seen from far away. The book lists this use as neon in discharge tubes and fluorescent bulbs for advertisement display; warning and signal lights use the same glow.
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
