aliphatic hydrocarbons

Test-(Chemistry) Aliphatic Hydrocarbons Class:……….. MM………… Questions: 1. 1-butyne on reaction with not alkaline KMnO4 gives: (a) CH3CH2CH2COOH (b) CH3CH2COOH+CO2 (c) CH3CH2COOH (d) CH3CH2CH2COOH+HCOOH 2. 2-methypentene-2 on ozonolysis will give: (a) Only propanal (b) Propanal and ethanal (c) Propanone-2 and ethanal (d) Propanone-2 and propanal 3. Which one of the following can distinguish propyne from propene: (a) Br2 water (b) Ammoniacal AgNO3 (c) Aq.KMnO4 (d) Dil.H2SO4 4. To prepare a pure sample of n-hexane using sodium metal as one reactant, the other reactant or reactant will be: (a) Ethyl bromide and n-butyl chloride (b) Methyl bromide and n-pentyl bromide (c) n-propyl bromide (d) Ethyl bromide and n-pentyl bromide 5. An alkene, obtained by the dehydration of an alcohol (A), ozonolysis gives two molecules of acetaldehyde for every molecule of alkene. The alcohol (A) is (a) CH3CH2CH2OH (b) CH3CH2OH (c) CH3CH=CHCH2OH (d) CH3CH2CHCH3 | OH 6. Identify Z in the sequence, CH3 – CH – CH2 – O – CH2 – CH3 | CH3 CH3 – CH2 – CH – O – CH2 – CH3 | CH3 CH3 –(CH2)3 – O – CH2 – CH3 CH3 –(CH2)4 – O – CH3 7. The most suitable reagent to distinguish compound (iii) from the rest of the compound is (i) (ii) CH3 – CH2 – CH2 – CH3 (iii) CH3 – CH2 - CCH (iv) CH3 – CH = CH2 Bromine in CCI4 Bromine in CH3COOH Alkaline KMnO4 Ammoniacal AgNO3 8. Acetylene reacts with HCN in the presence of Ba (CN)2 to yield: (a) Vinyl cyanide (b) 1,1-dicyanoethane (c) 1,2 – dicyanoethene (d) None 9. Action of NH3 over C2H2 at high temperature gives: (a) Amine (b) Furan (c) Thiophene (d) Pyrolle 10. Action of Br2 on cyclopentene gives: (a) 1,2- dibromo on cyclopentene (b) Cyclopentyl bromide (c) Cyclopentyl dibromide (d) No rection 11. An alkyl bromide (X) reacts with Na to from 4, 5-diethyl octane. Compound (X) is: (a) CH3 (CH2)3Br (b) CH3 (CH2)5Br (c) CH3 (CH2)3 CHBr . CH3 (d) CH3 (CH2)2 CHBrCH2 CH3 12. called: (a) Clemmensen reduction (b) Fisher-Spier reduction (c) Birch reduction (d) Arndt-Eistert reduction 13. Addition of HI on double bond of propene yields isopropyl iodide and not n-propyl iodide as the major product, because addition proceeds through: (a) A more stable corbonium ion (b) A more stable carbanion (c) ) A more stable free radical (d) None 14. Which of the following will have least hindered rotation about carbon-carbon bond: (a) Ethane (b) Ethylene (c) Acetylene (d) Hexachloraethane 15. Which of the following is elimination reaction: (a) (b) (C) (D) All are correct. 16. Which of the following characteristic apply both to ethane and ethyne: (a) Explode when mixed with chlorine (b) Decolourise Baeyer’s reagent giving brown precipitate (c) Rapidly absorbed by cold conc. H2SO4 (d) From white precipitate with AgNO3 solution. 17. At low temperature, the slow addition of molecular bromine to H2C = CH – CH2 – CCH gives CH2 = CH – CH2 – CBr = CHBr BrCH2 – CHBr – CH2 – CCH H2C = CH – CH2 – CH2 – CBr3 CH3 – CBr2 – CH2 – C CH The number of bonds possessed by each carbon atom of acetylene is (a) 4 (b) 3 (c) 2 (d) 1 19. . Y is (a) CH2OH – CH2OH (b) CH3CH2OH (c) CH3COOH (d) CH3OH 20. Which of the following has the least octane number: (a) Octane (b) Cetane (c) 2,2,4-trimethyl pentane (d) Ethanoic acid 21 Reactivity of tertiary H, secondary H and primary H towards elimination is: (a) Tert. > Sec. >Pri (b) Sec. > Tert. > Pri. (c) Sec. > Pri. > Tert. (d) Pri. > Sec. > Tert. 22. The distinguishing test for triple bond containing acidic hydrogen is: (a) Br2 in CC14 (b) Alkaline KMnO4 (c) Ag(NH3)2+ (d) Glycerols 23. To enable easy detection of gas leakage from cylinders, the substance added to LPG is: (a) Glocols (b) Phenols (c) Thioalcohols (d) Glycerols 24. The marsh gas detector used by miners works on the principle of: (a) Difference in the rates of diffusion of gases (b) Avogadro’s hypothesis (c) Gay-Lussac’s law of gaseous volumes (d) Berzelius hypothesis 25. The compound most likely to decolourize a solution of potassium permanganate is: (a) CH3CH3 (b) (c) CH3CH = CHCH2CH3 (d) 26. Ethyl alcohol is heated with conc. H2SO4. The product formed is: (a) (b) C2H6 (c) C2H4 (d) C2H2 27. What is the end product of the following sequences of operations: (a) Methyl alcohol (b) Acetaldehyde (c) C2H5OH (d) C2H4 28. An octane number 100 is given to: (a) n-hexane (b) Iso-octane (c) Neopentane (d) Neo-octane 29. Acetylene when passed through 40% sulphuric acid at 80oC gives aceltabdehyde. The catalyst required for this reaction is: (a) Anhydrous aluminium chioride (b) Mercuric sulphate (c) Palladium (d) Platinum 30. Extensive branching of carbon chain in pentane: (a) Decrease the b.pt. (b) Decrease the molecular weight (c) Increase the b.pt. (d) increase the molecular weight 31. A hydrocarbon react with HI to gives (X) which on reacting with aqueous KOH forms (Y). Oxidation of (Y) gives 3-methyl, 2-butanone. The hydrocarbon is: (a) (b) (c) (d) 32. The order of appearance of the following with rising temperature during the refining of crude oil is: (a) Kerosene, gasoline, diesel (b) Diesel, gasoline, kerosene (c) Gasoline, diesel, kerosene (d) Gasoline, kerosene, diesel 33. Reduction of 2-butyne with Na in liquid NH3 gives predominantly: (a) n-butane (b) Trans-2-butene (c) No reaction (d) Cis-2-butene 34. Which one of the following has the smallest heat of hydrogenation per mole: (a) 1-butane (b) Trans-2-butene (c) Cis-2-butene (d) 1,3-butadiene 35. Which one among the following is assigned an octane number of zero: (a) Iso-octane (b) n-heptane (c) Isoheptane (d) 2-methyloctane 36. The reaction, (a) Eglinton’s reaction (b) Glaser reaction (c) Gomberg- Beckmann’s reaction (d) Leuckart reaction 37. Out of the following fractions of petroleum the one having the lowest boiling point is: (a) Kerosene (b) diesel oil (c) Gasoline (d) Heavy oil 38. Viscosity coefficients of some liquids are given below, Liquid in millipoise at 30oC CH3(CH2)3CH3 2.11 CH3(CH2)4CH3 2.89 CH3(CH2)5CH3 3.68 The order of viscosity coefficient of the liquid, (A) (B) (C) (a) will be the same (b) (A) > (B) > (C) (c) (A) < (B) < (C) (d) (A) > (B) = (C) 39. The catalytic hydrogenation is more easier is case of which alkene: (a) (b) (c) (d) 40. Gasoline is: (a) C3H8 to C6 H14 (b) C7H16 to C10 H22 (c) C7H24 to C14 H34 (d) C17H36 to C21 H50 Keys 1d 2d 3b 4c 5d 6c 7d 8a 9d 10a 11d 12c 13a 14a 15d 16b 17b 18a 19a 20d 21a 22c 23c 24a 25c 26c 27c 28b 29b 30a 31b 32d 33b 34d 35b 36a 37c 38b 39b 40d Solutions: 1 2. 3. Propyne gives white ppt. with ammoniacal 4. Wurtz reaction. 5. Alkene is asymmetrical alkene and therefore alcohol is, which will give alkene-2 as major product 6. 7. Amm. Gives white ppt. with terminal alkyne. 8. vinyl cyanide 9. 10. 11. 12. It is the name of reaction. 13. Follow mechanism of addition reactions. 14. Least hindered rotation means free rotation, i.e., round a single bond. 15. It involves removal of a molecule from substrate. 16. Both are unsaturated and give Baeyer’s test. 17. Addition of HBr first takes place round double bond. 18. Each carbon atom in an organic compound has four bonds. 19. 20. The octane no. for n-between is zero. 21. The reactivity order of H atoms has been explained in terms of hyper conjugation. 22. gives white ppt. with terminal alkynes. 23. Thicoalcohol (or mercaptons) have unpleasant odour, is commonly used. 24. CH4diffuses rapidly because of low mol. wt. 25. It is a test for unsturation. No doubt naphthalene (b) is also unsaturated but it is stabilized due to resonance and thus do not give Baeyer’s test. 26. This is elimination process. 27 28. Octane no. for iso-octane has been arbitrarily assumed to be 100 and for n-heptane as zero. 31 32. AT 70-120o C gasoline, At 150-250oC kerosene; At 250-400oC diesel oil. 33. 34.Conjugated alkadienes are more stable and possess lower heat of hydrogenation. 36. It is the name of reaction. 37. Gasoline mixture has lower carbon atoms alkenes and thus have lower b.pt. 38. Large is surface area, more is viscosity. Surface area decreases with increases in branching. 39. Cataytic hydrogenation is free radical addition. Also more is heat of hydrogenation more is reactivity for alkene for hydrogenation. 40. Gasoline contains alkenes from carbon atom. Aliphatic Hydrocarbons 1 *** Shallu Aggarwal Mobile #. 98786-08983 ***