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| 31)Chemically dry ice is | |||
| solid carbon dioxide | solid sulphur dioxide | ||
| ice kept at sub-zero temperature | ice formed from pure distilled water | ||
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| 32)A gas which is not present in normal samples of air is | |||
| neon | carbon dioxide | ||
| chlorine | helium | ||
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| 33)A catalyst is a substance which | |||
| helps initiate a reaction | increase the speed of reaction | ||
| decrease speed of reaction | stops chemical reaction | ||
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| 34)Of the following, the content of carbon is minimum in | |||
| steel | pig iron | ||
| cast iron | wrought iron | ||
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| 35)Marsh gas, formed from decaying organic matter and in coal mines is | |||
| methane | ethane | ||
| carbon monoxide | carbon dioxide | ||
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| 36)The acid used in batteries is | |||
| acetic acid | hydrochloric acid | ||
| sulphuric acid | nitric acid | ||
| Answer : | |||
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| 37)Vinegar is acidic in nature due to the presence of | |||
| sulphuric acid | citric acid | ||
| hydrochloric acid | acetic acid | ||
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| 38)The acid present in lemons and oranges is | |||
| acetic acid | hydrochloric acid | ||
| oxalic acid | citric acid | ||
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| 39)Water for civil supplies is commonly purified by | |||
| filtration | chlorination | ||
| distillation | decantation | ||
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| 40)During fermentation of sugar the chief compound always formed is | |||
| methyl alcohol | ethylene | ||
| ethyl alcohol | acetic acid | ||
| Answer : | |||
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| 41)Fixation of nitrogen implies | |||
| the conservation of atmospheric nitrogen into useful compounds | the liquefaction of nitrogen | ||
| the conservation of nitrogen into amines | the solidification of nitrogen of the atmosphere | ||
| Answer : | |||
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| 42)Wood charcoal is commonly prepared by the process of burning wood | |||
| in contact with air | in contact with pure oxygen | ||
| in contact with nitrogen and inert gases | out of contact with air | ||
| Answer : | |||
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| 43)Animal charcoal is obtained by | |||
| burning the bones of animals in contact with air | the destructive distillation of bones | ||
| burning the bones of animals out of contact with air | burning the flesh of animals | ||
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| 44)The substance that is added to make natural rubber strong and bouncy is | |||
| sponge | sulphur | ||
| chlorine | sulphuric acid | ||
| Answer : | |||
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| 45)Photographic plates are covered with black paper because | |||
| sunlight is easily absorbed by black paper and it helps develop the film | the cellulose acetate of the paper must remain fresh | ||
| the conservation of silver bromide to metallic silver is essential | silver bromide present on the plate is very sensitive to light and black paper prevents contact with light | ||
| Answer : | |||
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