$A$ dilute solution of $HCl$ cannot be concentrated beyond ...... $\%$ by boiling.

The boiling point of an azeotropic mixture of water-ethanol is less than that of both water and ethanol. Then

Which of the following statements is true?

Components of a binary mixture of two liquids $A$ and $B$ were being separated by distillation. After some time,the separation of components stopped and the composition of the vapour phase became the same as that of the liquid phase. Both the components started coming in the distillate. Explain why this happened.

An azeotropic solution boils at a temperature lower than the boiling point of any of its components. This solution shows:

When do azeotropic mixtures of two liquids boil at a temperature lower than their boiling points?