2nd Year Chemistry Chapter 8 Aliphatic Hydrocarbons Solution

chemistry 12th notes chapter No 8

1. Which of the following gases is used for artificial ripening of fruits:


2. What type of reaction occurs between Ethene and hydrogen:


3. Polymerization of Ethene to Polyethylene take place at pressure of 100 atm and a temperature of:


4. During the preparation of alkynes the active metals that reacts with Tetrahalo-alkane is:


5. Formula of chloroform is:


6. The property of an alkane which does not increase with increase in molar mass:


7. The method in which alkane is prepared by Alkyl halide in the presence of Palladium charcoal, is:


8. The number of xylene isomers is:


9. Alkanes are soluble in all except:


10. Polymerization of acetylene forms:


11. An Alkane is produced when an Alkyl halide reacts with Zinc in the presence of a catalyst; the reaction is called:


12. Alkyl halides on treatment with active metals like Zn yield:


13. An Alkyne having Carbon atoms =15 is most probably a:


14. Formula of lindlers catalyst is:


15. Hydrocarbon which is liquid at room temperature is:


16. The major reaction occurring in the engines of automobiles is:


17. Ethyl chloride when boiled with alcoholic KOH gives:


18. Acetylene has a characteristic smell resembling that of:


19. Vinyl acetylene combines with HCl to yield:


20. Which ion is most stable:


21. Kolbe’s method is not useful for the production of:


22. The reaction/method that does not give an alkane is


23. Which of following is used as a general anesthetic:


24. The addition of unsymmetrical reagent to an unsymmetrical alkene is in  accordance with the rule:


25. The Alkynides are used for the ———-of alkynes


26. When Sodium Salts of fatty acid are heated with Sodalime, we get alkane along with:


27. Ammonical solution of silver nitrate reacts with:


28. A fuel has the same knocking property as a mixture of 70 percent Iso-octane (2, 2, 4- Trimethylpentane) and 30 percent n-Heptane by volume, the octane number of that fuel is:


29. Select the compound which has acidic hydrogen:


30. Which of following is prepared by oxidation of Ethane:


31. Mustard gas is:


32. Kolbe’s method has limited synthetic applications due to:


33. The low reactivity of alkanes is based upon:


34. Acetylene gives:


35. Marsh gas was the name given to:


36. The alkenes react with aqueous solution of halogen acid to form:


37. Synthetic rubber is made by the polymerization of:


38. Polymerization of three molecules of acetylene while passing through Cu tube at 300 ⁰C gives:


39. CₙH₂ₙ is the general formula of:


40. Unsaturated nature of alkene can be detected by:


41. Raney – Nickel is the alloy of Ni with:


42. The characteristic reactions of alkanes are:


43. Vicinal dihalides on treatment with Zn-dust give:


44. The order of reactivity of halogen acids towards alkenes:


45. The reaction in which a Ketone is reduced to the alkane is called:


46. The presence of pi bond in a molecule is the sign of :


47. When ethylene ozonide is treated with Zn-dust we get:


48. For preparing a symmetrical alkane, a concentrated aqueous solution of sodium or potassium salt of saturated carboxylic acid is subjected to:


49. Which of the following compound will not form Metal alkynide:


50. Each different compound should have a different name” was published by IUPAC system of nomenclature in:


51. CH₃ is an example of:


52. The order of reactivity of halogens in aliphatic substitution reactions:


53. Complete combustion of alkane yields:


54. The most reactive hydrocarbon is:


55. The characteristic reactions of alkenes are:


56. Chemically Baeyer’s reagent is:


57. Alkanes containing carbons C-18 onwards are:


58. Hydroxylation of alkene can be carried out by:


59. For each double bond, the heat of hydrogenation of Alkene is:


60. Incomplete oxidation of alkanes yields:


61. The IUPAC name of the compound having the formula (CH₃)₃ C – CH = CH₂ is:


62. The gas used for illumination:


63. Alkynes are colorless & odorless except:


64. Cycloalkanes and Alkenes contain which general formula:


65. The reaction of Acetylene with water in H₂SO₄ and HgSO₄ yields:


66. Preparation of vegetable ghee involves:


67. An Aldehyde is reduced to Alkane with:


68. Write the name of following Alkene CH₂ = CH⁻ CH = CH₂


69. When a mixture of Ethene and air is passed over heated silver under pressure we get:


70. Number of acidic hydrogens present in 1-butyne is:


71. Which type of reactions are given by alkanes:


72. Which of the following is not alicyclic:


Short Questions

1. Benzene can be prepared commercially from acetylene. Give reaction conditions?
2. Briefly tell why alkanes are less reactive than alkenes?
3. Give the equations and necessary conditions for the polymerization of ethene into polythene?
4. Give the general formulas for alkanes alkenes and alkynes?
5. Give the mechanism of ozonalysis of propene?
6. Give the nature of products in the chemical equations by catalytic oxidation of methane?
7. Give the nature of the products when sodium salt of propanoic acid is electrolysed in Kolbe’s electrosynthesis?
8. Give the reaction conditions and the reagents which are necessary for dehalogenation of vicinal dihalides?
9. Give the uses of acetylene?
10. How ammonical solution of Cu₂CI₂ can be used to distinguish between 1-butyne and 2-butyne?
11. How ammonical solution of AgNO₃ can be used to distnguish betweenb 1- butyne and 2-butyne?
12. How chloroprene is produced by the polymerization of acetylene?
13. How do you convert alkynes into cis and trans alkenes?
14. How do you distinguish between ethene and ethyne?
15. How does sodamide react with alkynes? What are the applications of this reaction?
16. How ethyne can be prepared by Kolbe’s electrosynthesis?
17. How Kolbe’s electrosynthesis gives us ethane from sodium succinate?
18. How many alkyl groups can be generated by an alkane with molecular formula C₄H₁₀?Give the name of alkyl groups?
19. How mustard gas is prepared?Give its properties and uses.
20. How the alkenes are converted into epoxide and what are their appliications?
21. How the alkenes can be converted into alcohols?
22. How the reactions of Grignard’s reagent with active hydrogen compounds give alkanes with the same number of carbon aoms as present in the alkyl group of Grignard’s reagent?
23. How vicinal dihalldes are converted into corresponding alkynes?
24. Indicate the mechanism for the addition of a bromine on propene?
25. Justify that dehydrohalaogenation of alkyl halides give alkenes?
26. Justify that the order of reactivity of alcohols for dehydration purposes is as follows:Ter.Alcohol>Sec.alcohol>Prim.alcohol.
27. Reason out the low reactivity of alkanes among the hydrocarbon family?
28. The nitration of higher hydrocarbons breaks the carbon carbon bond..How HNO₃ reacts with CH₄?
29. The reaction of chlorine with CH₄ has a free radical mechanism. Justify it?
30. What are hydrocarbons? Give one example of each type of hydrocarbon?
31. What are monoenes dienes and polyenes?Give one example of each?
32. What are the applications of hydrogenation of unsaturated cpmpounds to saturated compounds in the labortary and industry?
33. What are the most important dehydrating reagents to convert alcohols into alkenes?
34. What are the reduction producs of alkyl halides.Indicate the important reducing agents purpose?
35. What do you mean decarboxylation of carboxylc acids?
36. What is Baeyer’s test to check the presence of carbon carbon double bond?
37. What is hydrogenolysis?
38. What is Markownikoff’s rule?Give its applications for the addition of HBr on propene?
39. What is Raney nickel and where is it used?
40. What is Sabatier-Sendern’s reaction?
41. What is the effect of branching on the meltin points of alkanes?
42. What is the importance of Wurtz synthesis for the manufacture of alkanes?
43. What is the important of hydrogenation of unsaturated compounds?
44. What is the role of combustion of ethyne in daily life?
45. Why alkenes are called olefins?
46. Why some hydrocarbons are saturated and other unsaturated?What type of reactions are characteristics of them?
47. Why the saturated hydrocarbons act as good fuels?
48. Why the π bond is more rective than o-bond?
49. Write the equation for the conversions of aldehyde and ketones into corresponding alkanes?

Long Questions

1. Explain free radical mechanism for the reaction of chlorine with methane in the presence of sunlight.
2. Write two methods for the preparation of Alkanes from Alkyl halides.
3. Prepare Ethane From Kolbe’s Electrolytic method. Also write down its mechanism.
4. Explain with equations how Alkanes can be prepared from (i) Acids
5. Write a note on halogenations of alkanes.
6. Discuss any two method of preparation of alkenes.
7. Write balanced equations for the reactions of ethene with: (i) O₂/Ag (ii) S₂ Cl₂ (iii) KMnO₄ (iv) HOCI
“8. Write the chemical reaction of ethene with the following.
(i) HCI (ii) Br₂ (iii) O₃ (iv) HOX”
“9. Write the reactions of ethene with:
(i) Br₂ (ii) O₃ (iii) HBr (iv) HOCI”
“10. Write the reaction of propene with:
(i) H₂/Ni (ii) Cone.H₂SO₄ (iii) HCI”
11. What happened when ethene is reacted with KMnO₄, HBr and S₂Cl₂.
“12. How will you convert ethane into
Ethyl alcohol (ii) Ethylene Epoxide (iii) Ethylene glycol (iv)Ethylene”
13. What is Markownikov’s Rule? Give two examples.
“14. How will you make the following conversion.
Ethene into ethanol (ii) Ethanol into 2-Butanone”
“15. How will you make the following conversions from an alkene;
(i) 2- Bromo-2methylpropane (ii) propylene oxide
(iii) 2-Bromopropane. (iv) 2-propanol”
“16. Give the chemical reactions of ethene with:
(i) S₂Cl₂ (ii) HOCI (iii)O₂ in the presence of Ag₂O (iv) Conc. H₂SO₄”
“17. Starting from ethene, outline the reactions for preparation of the following compounds.
(i) 1,2 dibromoethane (ii) Ethyne (iii) Ethane (iv) Ethylene glycol”
18. How Kolb’s electrolysis method is used for preparation of alkenes & alkynes.
“19. Give the preparation of ethyne by:
Dehydrohalogenation of vicinal dihalide (ii) Kolbe’s electrolytiic method”
20. Describe mechanism for the electrolysis of potassium maleate to prepare ethyne.
21. Discuss acidic nature of alkynes with at least two examples.
22. Show the reactions that ethene and ethyne are unsaturated. How can they be distinguished? Complete also the corresponding chemical reaction.
23. Write a note on polymerization of ethyne.
24. Describe how you could distinguished ethane, ethene ethyne from one another by means of chemical reactions.
“25. How does ethyne react with:
(i) Hydrogen (ii) Halogen acid (iii) Alkaline KMnO₄”
“26. How will you Synthesize the following compounds starting from ethyne.
(i) Chloroprene (ii) Glyoxal (iii) Methyl nitrile (iv) Acetaldehyde.”
27. How will you distinguish ethane, ethene and ethyne.
“28. How acetylene can be converted into:
(i) Acetaldehyde (ii) Chloroprene (iii) Acrylonitrile (iv) Divinyl acetylene”
“29. How will you convert ethyne to
(i) Ethane (ii) Acetaldehyde (iii) Divinyl acetylene (iv) Glyoxal”
30. Make the following changes. (i). Aeration (iii) Ethyne into Benzene.
“31. How will you bring about the following conversions?
(i) 1-butane Into 1 – butyne
(ii) acetylene into chloroprene”
“32. Synthesize:
(i)Oxalic acid (ii) Methyl nitrile
(iii) Acetaldehyde (iv) Acrylonitrile starting from ethyne.”
33. Give comparison of reactivates of alkane, alkene and alkyne.
“34. How will you prepare following from ethyne (Equations only)
(i) Acetaldehyde (ii) Benzene (iii) Ethane (iv) Oxalic acid”
35. How will you bring about the following conversions. (i) Methane to Ethane (ii) Acetic acid to Ethane
“36. Discus the following terms with respect to alkenes with suitable chemical reactions.
(i) Ozonolysis (ii) Hydroxylation”
“37. Write down the structural formulae for the products formed when reacts with
(i) Cold dil. KMnO₄ /OH⁻ (ii)HBr (iii) O₂ in the presence of Ag₂O (iv) HOCl”
“38. Prepare alkenes from
(i) carbonyl compounds (aldehyde and etones) (ii) Grignard reagent (iii) Alkyl halide”
39. How is ethyne react with: (i) Alkaline KMnO₄ (ii) 10 % H₂SO₄(iii) HBr
“40. Describe preparation of ethane (CH₃-CH₃) by each of the following methods:
By carboxylation of monocarboxylic acid (ii)Kolbe electrolysis method”
41. Write down methods for preparation of alkenes.
42. Write down four methods for How will you prepare Acetylene from: (i) Vicinal Dihalide (ii) Tetrahalide,
43. Give Polymerization Reactions of Ethyne to Prepare : (i) Divinyl Acetylene (ii) Synthetic Rubber (iii) Benzene
44. Give the preparation reactions of alkanes from (ii) Alkyl Halides (i) Carbonyl compounds

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