Question

Blood is a ………… charged sol.
A) Positively
B) Neutral
C) Negatively
D) None of these

Answer 1

Hint: The mixture in which one substance is divided into very minute particles is known as a colloid. An aggregate of very fine solid particles dispersed in a fluid is known as a sol. A sol is a type of colloid.

Complete answer:
Body contains an anticoagulant called heparin. Heparin does not allow the blood to coagulate.
Heparin has very high negative charge density. Heparin is produced in the body by the basophils and mast cells.
Blood thus becomes negatively charged due to presence of negatively charged heparin in it.
Thus, blood is a negatively charged sol.

Thus, the correct option is (C) negatively.

Additional Information: The colloidal particles possess an electrical charge. The fluid used for dispersion possesses a charge opposite to that of the colloidal particles. Thus, the charges are balanced and the colloidal solution becomes electrically neutral. The stability of colloidal solution depends on the charge possessed by it.
Colloidal solutions have very minute particles and they are not visible by naked eyes.
If the fluid used for dispersion of colloids is water then the sol is known as hydrosol. If the fluid used for dispersion of colloids is air then the sol is known as aerosol.

Note: Haemoglobin in blood is positively charged. It is inside the red blood cell. The membrane of the red blood cell is negatively charged.
Examples of positively charged sols: Haemoglobin, metal hydroxides, basic dyes, etc.
Examples of negatively charged sols: Metal sols, metal sulphides, gold sols, blood, starch, acidic dyes, etc.