Answer: The correct answer is Option 4.
Explanation:
For the given options:
Option 1: Evaporation is the process in which liquid starts to convert to gaseous state.
Option 2: Distillation is defined as the process of separating mixtures which are based on the differences in their volatiles in a boiling liquid mixture.
Option 3: Filtration is defined as the process of separating suspended solid particles from a liquid mixture.
Option 4: Titration is defined as the process where a solution of known concentration is used to determine the concentration of an unknown solution.
A known concentration of hydrochloric acid is given and we need to find the unknown concentration of sodium hydroxide, so we use the process of titration.
Hence, the correct answer is Option 4.
