232. Pick up the correct statement from the following :
A. Rusting is caused due to combined action of air, moisture and carbon dioxide
B. During rusting, first ferrous bicarbonates are formed
C. On further oxidation ferrous bicarbonates get converted to ferric bicarbonates
D. All the above.
233. German silver is an alloy of
A. zinc, lead and nickel
B. silver, gold and lead
C. copper, nickel and zinc
D. copper, nickel and zinc
234. PVC stands for
A. plastic very compact
B. polythene vinyl chloride
C. polythene vinyl carbon
D. polythene vanadium carbide.
235. Stainless steel resists corrosion due to
A. carbon
B. sulphur
C. vanadium
D. chromium
236. Brass is an alloy of
A. copper and zinc
B. zinc and lead
C. tin and silver
D. zinc and nickel
237. The rocks which are formed due to cooling of magma at a considerable depth from earth's surface are called
A. Plutonic rocks
B. Hypabyssal rocks
C. Volcanic rocks
D. Igneous rocks.
238. The rocks which are formed due to pouring of magma at the earth's surface are called
A. Plutonic rocks
B. Hypabyssal rocks
C. Volcanic rocks
D. Igneous rocks
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