16. Glass is made of the mixture of
A. quartz and mica
B. sand and silicates
C. salt and quartz
D. sand and salt
17. The vast resources of unutilised natural gas can be used in the production of
A. graphite
B. Synthetic petroleum
C. fertilisers
D. carbide
18. Paper is manufactured by
A. Wood and resin
B. Wood, sodium and bleaching powder
C. Wood, calcium, hydrogen sulphite and resin
D. Wood and bleaching powder
19. Gypsum is added to cement clinker to
A. increase the tensile strength of cement
B. decrease the rate of setting of cement
C. facilitate the formation of colloidal gel
D. bind the particles of calcium silicate
20. Soap is a mixture of sodium or potassium salts of
A. dicarboxylic acids
B. monocarboxylic acids
C. glycerol
D. tricarboxylic acids