Question
Question: The noble gas which was first discovered in the sun and then on the earth: A. Argon B. Xenon ...
The noble gas which was first discovered in the sun and then on the earth:
A. Argon
B. Xenon
C. Neon
D. Helium
Solution
Hint: Nuclear fusion takes place in the sun. Due to this hydrogen in the sun is converted to Helium. Helium has low boiling point, low density and is inert. “The main use of helium is as an inert protection gas in autogenous welding”.
Complete step by step solution:
We first need to understand what noble gases are. In the periodic table, Noble gases belong to the group 18. Traditionally they were called as group 0 in the periodic table because for decades after their discovery, no compound was found containing noble gases and therefore it was believed that they did not react with other atoms.
Some of these elements are abundant on earth as well as in the universe although their abundance decreases as we go down the group. Both Helium and Hydrogen are present in large quantities in the universe.
The first noble gas to be discovered was Argon in 1784 and was isolated in 1895. Helium was first discovered in the sun in 1868 before it was found on earth. A yellow line was observed by a French astronomer named Pierre-Jules-César Janssen while studying a total solar eclipse in 1868. This line had a wavelength of 587.49 nanometres that could not be produced by any element known at the time. It was hypothesized that a new element on the sun was responsible for this mysterious yellow emission and was named helium by Sir Norman Lockyer, an English astronomer.
Later in 1895, Sir William Ramsay, a Scottish chemist, conducted an experiment with a mineral containing uranium called cleveite by exposing it to mineral acids and collecting the gases that were produced. Lockyer and Sir William Crookes identified the helium within the samples sent by Ramsay. Around the same time as Ramsay, two Swedish chemists, Nils Langlet and Per Theodor Cleve, independently found helium in cleveite.
Therefore the correct answer is (d) Helium.
Note: Do not get confused between argon and Helium. Argon was the first noble gas to be discovered whereas Helium was first noble gas to be discovered in the sun and later on earth.