Name the method used for the separation of a mixture of iodine and sodium chloride.

Which of the following substances is not an element?

Which of the following undergoes sublimation?

$A$ mixture of sodium chloride and ammonium chloride is separated by:

Given below are two statements :
Statement-$I$: Sublimation is used for the separation and purification of compounds with low melting point.
Statement-$II$: The boiling point of a liquid increases as the external pressure is reduced.
In the light of the above statements, choose the correct answer from the options given below :

One sample of atmospheric air is found to have $0.03\%$ of carbon dioxide and another sample $0.04\%$. This is evidence that