23. Why when removing from the surface of the tissue of

23. Why when removing from the surface of the tissue of a greasy stain, it is recommended first to wet the edges of the spot with the solvent, and not the center?
If you do not open the file - install the RAR archiver. Inside the archive you will find a solution in Word format.
Questions and problems from the manual:
"Laboratory Workshop on Colloid Chemistry" Nekrasov AP, Veretenchenko BA, Kharkov NTU "KhPI", 2004
"Characteristic properties of disperse systems" Nekrasov AP, Kharkov, 1996
Tasks are executed in Microsoft Word, graphics - in Microsoft Exel or OriginPro; formulas are typed in the MathType editor (if the formulas contain unreadable characters, then you need to install this editor); files are archived by WinRAR.