272. Setting of cement is due to
     (a) hydration
     (b) dehydration
     (c) dialysis
     (d) osmosis
Ans: (a)
273. Proteins are polymerisation products of
     (a) aldehydes
     (b) alkenes
     (c) amino acids
     (d) alkynes
Ans: (c)
274. The artificial silk produced from cellulose is
     (a) Polyethylene
     (b) Nylon
     (c) Terylene
     (d) Rayon
Ans: (d)
275. Plastics are synthetic
     (a) rubbers
     (b) fibres
     (c) resins
     (d) sugars
Ans: (c)
276. The raw materials used in the manufacture of cement are
     (a) brimstone and silica
     (b) limestone and clay
     (c) brimstone and clay
     (d) brimstone and limestone
Ans: (b)
277. Glass is a ______ mixture of metallic ______.
     (a) homogeneous, sulphates
     (b) heterogeneous, nitrates
     (c) heterogeneous, carbonates
     (d) homogeneous, silicates
Ans: (d)
278. Physico-chemical characteristics of water in water sources undergo changes due to
     (a) aquatic macrophytes
     (b) aquatic fungi
     (c) effluents
     (d) evapotranspiration
Ans: (a)
279. Iodine in alcohol is known as
     (a) quick lime
     (b) tincture iodine
     (c) rectified spirit
     (d) None of these
Ans: (b)