_______ (Rast/Solvay) method involves the determination of the melting point of camphor and its solution.

Hint: As we know that camphor possesses a high melting point and its cryoscopic constant value is also very high due to which it has a high molal depression constant as well. So now we have to tell the method involved in the determination of the melting point of camphor and its solution.

Complete answer:
-Let us discuss about camphor and the method used to determine its melting point as follows:-
-Camphor: It is a waxy, flammable and transparent solid with a strong aroma. It belongs to the terpenoid category. It is sublime and due to its sublimation property, it has various applications.
-It possesses a high melting point and its cryoscopic constant value is so high as a result of which it has a high molal depression constant as well. So to determine the melting point of such compounds an old method is preferred which is known as the Rast method.
-It is a method which is used to identify the molar mass of an unknown solute. In this method, the first step is to identify the depression of the freezing point of the solution after the solute is added to it which in turn helps to identify the molar mass of that unknown solute which was added. This method is used for camphor as its melting point is very high.
-Hence Rast method involves the determination of the melting point of camphor and its solution.

Note:
-There are several methods to determine the molar mass and melting point which includes depression in freezing point, osmotic pressure, elevation in boiling point, etc. So study and understand all these methods and apply these colligative properties for such types of questions.