Question

Which of the following has the highest boiling point?

Options:

(a) Helium

(b) Argon

(c) Krypton

(d) Neon​

Answer 1

❗ ANSWER ❗

The melting and boiling points of noble gases are very low in comparison to those of other substances of comparable atomic and molecular masses.

This indicates that only weak van der Waal's forces or weak London dispersion forces are present between the atoms of the noble gases in the liquid or the solid state.

The van der Waal's force increases with the increase in the size of the atom, and therefore, in general, the boiling and melting points increase from He to Rn.

Helium boils at 2690C.

Argon has larger mass than helium and have larger dispersion forces. Because of larger size the outer electrons are less tightly held in the larger atoms so that instantaneous dipoles are more easily induced

resulting in greater interaction between argon atoms. Therefore, its boiling point (1860C) is more than that of He.

Similarly, because of increased dispersion forces, the boiling and melting points of monoatomic noble gases increase from helium to radon.

So among the given noble gases Xe is having maximum boiling point

Hope it's helpful dear..........

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Answer 2

Answer:

(a) Helium

Explanation:

Helium-4 is unique in having two liquid forms. The normal liquid form is called helium I and exists at temperatures from its boiling point of 4.21 K (−268.9 °C) down to about 2.18 K (−271 °C). Below 2.18 K, thermal conductivity of helium-4 becomes more than 1,000 times greater than that of copper.