Materials and Construction

181. Glass is corroded by

1. Fluorine (dry or wet)
2. Sulphuric acid
3. Phosphoric acid
4. None of these

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182. Zinc is not used

1. For producing zinc base die casting alloys
2. In its oxide form as pigments
3. As anode for corrosion prevention in boiler
4. As an alloying element in various bronzes

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183. Glass lined vessels are not used for handling/storing

1. Dilute H₂SO₄
2. Dilute HNO₃
3. Dilute HCl
4. Hydrofluoric acid

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184. Graphite is a good

1. Thermal & electrical insulator
2. Conductor of heat
3. Conductor of electricity
4. Both (B) & (C)

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185. Graphite is corroded by

1. Sulphuric acid (10%)
2. Sea water
3. Hydrochloric acid
4. None of these

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186. Gun metal is an alloy of

1. Nickel, tin and copper
2. Copper, tin and zinc
3. Copper, phosphorus and nickel
4. Manganese, phosphorus and nickel

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187. Gunmetal and bronze are not corroded by the action of

1. Wet chlorine
2. Synthetic detergent solution
3. Hydrochloric acid (10%)
4. Nitric acid (< 25%)

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188. H2SO4 (< 50% concentration) is corrosive to

1. Aluminium, mild steel, stainless steel, concrete & tin
2. Copper, cast iron & high silicon iron (14% Si)
3. Rubber (butyl and hard), silicone rubber & Teflon
4. Glass, graphite, porcelain & stoneware

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189. Hammers and railway rails are normally made of

1. Mild steel
2. Dead mild steel
3. Medium carbon steel
4. High carbon steel

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190. Hardened steel is softened by

1. Normalising
2. Tempering
3. Annealing
4. Carburising

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