$MF + XeF_4 \to$ '$A$' ($M^{+} =$ Alkali metal cation). The state of hybridisation of the central atom in '$A$' and shape of the species are:

Total number of lone pairs of electrons in $XeOF_4$ is

Given below are two statements:
Statement-$I$: Noble gases have very high boiling points.
Statement-$II$: Noble gases are monoatomic gases. They are held together by strong dispersion forces. Because of this,they are liquefied at very low temperatures. Hence,they have very high boiling points.
In the light of the above statements,choose the correct answer from the options given below:

Assertion $(A)$: Helium has the lowest boiling point $(4.2 \ K)$.
Reason $(R)$: The forces that exist between helium atoms are weak dispersion forces.

Identify the inert gas used for filling balloons.

Which one of the following statements regarding helium is incorrect?