Question

which of the following noble gases does not form clathrates ?
(A). $He$
(B). $Kr$
(C). $Ar$
(D). $Xe$

Answer 1

Hint: A clathrate is a chemical substance consisting of a lattice that traps or contains molecules. The word clathrate is derived from the latin word, clathrates meaning with bars, latticed. clathrate is an ice-like compound formed when water freezes in presence of sufficient methane and other gases.

Complete step by step answer:
Clathrate is a structure in which water molecules under certain conditions bond to form complex networks of molecules forming a cage – like structures that encapsulate a guest molecule, which is a gas.
Krypton $\left(Kr\right)$ , chemical element, rare gas of group eighteen (noble gases) of the periodic table, which forms relatively few chemical compounds. Because its boiling point is about $30-{40}^{\circ }c$ higher than those of the major constituents of air, krypton is readily separated from liquid air by fractional distillation. Krypton is the lightest of the noble gases that form isolable chemical compounds in macroscopic amounts. Clathrate compounds, in which the element is trapped in cage-like structures of water or other molecules, are known. There is no diatomic molecule of krypton.
Calculations of the trapping of heavy noble gases within multiple guest clathrates under mars-like conditions show that a substantial fraction of the martian $Xe$ , perhaps then the most majority, could be in clathrates. In addition, the $Xe/Kr$ ratio in the clathrates would probably be much higher than in the atmosphere, so the formation or dissociation of a relatively small amount of clathrate could measurably change the atmosphere ratio – relatively crude measurements of the seasonal variability in that ratio by in sites spacecraft would be sensitive to $\sim 10\mathrm{\%}$ of the seasonal atmospheric $C{o}_2$ variability being a result of clathrates, rather than pure $C{o}_2$ frost. In addition, sequestration of $Xe$ in clathrates remains a viable $Xe/Kr$ ratio seen in different suites of martian meteorites.

So, the correct answer is Option A.

Note:
Other characteristics of the noble gases are that they all conduct electricity, fluorescence, are odorless and colourless, and are colourless, and are used in many conditions when a stable element is needed to maintain a safe and constant environment. The chemical series contains helium, neon, oxygen, krypton, xenon and radon.