Solved questions for Exam
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Q.1 Why is carbon tetravalent?
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Ans 1: Carbon atom has 4 electrons in the outermost shell.It needs 4 more electrons to complete its octet. Therefore, carbon is tetravalent .
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Q.2 The formula of a hydrocarbon is Cn H2n. Name the family to which it belongs and also predicts its nature.
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Ans 2: The hydrocarbon belongs to alkenes It is unsaturated in nature.
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Q.3 What is the valency of carbon in CH3-CH3, CH2=CH2 and HC=CH ?
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Ans 3: The valency of carbon in all its compounds whether saturated or unsaturated is 4.
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Q.4 Out of butter and ground nut oil , which is unsaturated in Nature?
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Ans 4: Groundnut oil is unsaturated in nature .
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Q.5 Why is high temperature not favourable for alcoholic fermentation?
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Ans 5: The high temperature destroys the enzymes which are needed to carry fermentation .
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Q.6 Name a cyclic unsaturated hydrocarbon, containing three double bonds?
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Ans 6: Benzene
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Q.7 What is the difference in the molecular mass of any two adjacent homologues?
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Ans 7 : 14 mass units.
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Q.8 Which has triple bond ; C2H4 ,C3H6 and C3H4 ?
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Ans 8:C3H4 has triple bond in the formula .
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Q.9 Which substance is added to denature ethyl alcohol?
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Ans 9: A small amount of methyl alcohol , pyridine or copper sulphate is added to denature ethyl alcohol .
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Q.10 Which ions are responsible for making water hard ?
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Ans 10: Ca2+ and Mg2+ ions are responsible for making water hard.
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Q.11 Name the catalyst commonly used in hydrogenation of oil to form fats?
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Ans 11:Nickel.
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Q.12 Write the name and molecular formula of alcohol derived from butane ?
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Ans 12: C4H9OH Butanol
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Q.13 Which gas is evolved when sodium carbonate or bicarbonate is added to ethanoic acid ?
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Ans 13 : CO2 (carbon dioxide).
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Q.14 What is SCUM ?
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Ans 14: Scum is precipitate of Calcium and Magnesium salt of organic fatty acids.
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Q.15 What are hydrophobic and hydrophilic parts in soaps?
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Ans : The alkyl group(R) consisting of long chain of carbon atom is hydrophobic part while COONa group is hydrophilic in nature
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