141. Non-stick cooking utensils are coated with: [I. Tax Central Excise 1993]
(a) black paint
(b) PVC
(c) teflon
(d) Polystyrene
Ans: (c)
142. Permanent hardness of water can be removed by adding: [NDA 1991]
(a) potassium permanganate
(b) chlorine
(c) bleaching powder
(d) washing soda
Ans: (d)
143. Which of the following is not correctly matched? [NDA 1993]
(a) Galena: Lead sulphide
(b) Green vitriol: Copper sulphate
(c) Plaster of Paris: Calcium sulphate
(d) Calomel: Mercurous chloride
Ans: (b)
144. The formula of plaster of paris is:
(a) CaSO2
(b) CaSO4 . 2H2O
(c) 2CaSO4 . 4H2O
(d) 2CaSO4 . H2O
Ans: (d)
145. Which of the following substances is a bad conductor of electricity but a good conductor of heat? [RRB1993]
(a) Asbestos
(b) Celluloid
(c) Purspecks
(d) Mica
Ans: (d)
146. Which of the following pairs does not contain a coinage metal? [CDS 1990]
(a) Copper and Gold
(b) Silver and Gold
(c) Zinc and Gold
(d) Copper and Silver
Ans: (c)
147. Which of following is an element? [IAS 1992]
(a) Ruby
(b) Sapphire
(c) Emerald
(d) Diamond
Ans: (d)
148. Most soluble in water is :
(a) camphor
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