11. The major ingredient of leather is
A. collagen
B. carbohydrate
C. polymer
D. nucleic acid
12. What are the soaps?
A. Salts of silicates
B. Mixture of glycerol and alcohols
C. Sodium or potassium salts of heavier fatty acids
D. Esters of heavy fatty acids
13. How does common salt help in separating soap from the solution after saponification?
A. By decreasing density of Soap
B. By decreasing solubility of Soap
C. By increasing density of Soap
D. By increasing solubility of Soap
14. In vulcanisation, natural rubber is heated with
A. Carbon
B. Silicon
C. Sulphur
D. Phosphorous
15. Deep blue colour is imparted to glass by the presence of
A. cupric oxide
B. nickel oxide
C. cobalt oxide
D. iron oxide