Sabtu, 01 Agustus 2009

HYDROCARBON REACTIONS PROBLEM

1. Alkanes are non polar molecules. Explain the reason by giving an example.

2. Alkanes are called 'parafin.' What is the meaning of 'parafin?

3. Alkanes are saturated hydrocarbons and therefore, are generally less reactive than alkenes. Explain the reason.

4. Alkanes are unreactive towards polar or ionic reagents. Why?

5. Alkanes react with Br2 only in the presence of UV light. Give an example.

6. Which of the following statements is (are) correct regarding the reactivity of alkanes? Explain please.
a. Alkanes are generally inert.
b. Alkanes are polar molecules.
c. Alkanes are often used as solvents.
d. Alkanes react with acid.
e. Alkanes react with halogens.
f. Alkanes react with oxygen.

7. Explain that alkanes contain only strong sigma bonds.

8. The electronegativities of C and H are about the same, so C-H bonds have no significant polarity. Explain please.

9. All hydrocarbons burn easily in oxygens. What is the name of this reaction? Explain this type of reaction.

10. What the difference between complete combustion and incomplete one?

11. The large negative ∆H’s (exothermic reactions) explain why hydrocarbons are useful as fuels. Explain please.

12. When hydrocarbons burn in a limited supply of air (O2), what will happen?

13. Write down the balanced equation of complete combustion of ethane, propene, butyne.

14. Hydrocarbons only burn in the gaseous state. Explain the meaning of this statement.

15. What are the products of the combustion of 4-methyl-2-hexene in a limited oxygen?

16. The reaction of alkanes with halogens is called substitution. Explain by using an example.

17. What relative amounts of 1-bromo butane and 2-bromobutane are actually formed when butane is brominated?

18. What is the major product obtained from the monobromination of 2-methylbutane in the presence of light at room temperature?

19. What is the major product obtained from the monochlorination of 2-methylbutane in the presence of light at room temperature?

20. Alkanes react with the halogens via free-radical substitution reaction in the presence of sunlight. Explain this type of reaction.

21. When methane reacts with chlorine in sunlight, so what will happen?

22. What is the meaning of a chain reaction?

23. The mechanism of chain reaction of a substitution consists of four steps. What are they? Explain each of them by using an example.

24. Alkenes are more reactive than alkanes. Explain the reason.

25. An addition reaction is a reaction in which parts of a reactant are added to each carbon atom of a carbon–carbon double bond in alkenes. Give an example please.

26. Addition to triple bonds is also possible. Explain please.

27. What is the different between addition reaction in alkenes and alkynes?

28. What is the meaning of hydrogenation?

29. What is the product of the hydrogenation of 1-pentene and 2-pentene?

30. Write the equation of addition of Br2 to 1-butene; 2-butene; 2-methyl-1-butene; 2-methyl-2-butene.

31. There is (are) color change when the following substance(s) is (are) mixed with bromine water. Please choose and explain: ethene; n-butane; 2-butene; 2-methylpropane; 2-methylbutane; Cyclobutane.

32. The addition of Br2 to an alkene occurs so readily that bromine dissolved in carbon tetrachloride, CCl4. It is a useful reagent to test for unsaturation. Explain the reason.

33. What are the products of the addition of Br2 to cyclobutene and 3-methyl cyclopentene. Write down the equation and the name of the products.

34. Write down the equation of the addition of Cl2 to 2-methyl-2-pentene and 4-methyl-2-pentene.

35. Complete the following equation and give the name of the products.
a. C2H4 + Cl2 -->
b. C3H6 + Br2 -->

36. If an excess of Br2 is added to CH ≡ CH, what is the correct product. Write down the rquation.

37. What the reactant used to produce the following prodcts? Write down the equation.
a. CH3CBr=CHBr
b. CHBr2-CHBr2
c. CHBr=CBrCH2CH3

38. What is the difference between substitution reaction and addition?

39. Explain the statement of Markownikoff’s rule

40. What is the main product when HBr adds to 1-pentene? Write the equation.

41. Write the equation of addition of HCl to 2-methyl-2-pentene.

42. If an excess of HCl is added to CH3CH2C≡CH, what is the product? Write the equation.

43. What is the product of addition of excess bromine to 2-propyne? Write the equation.

44. When calcium carbide is added to water, a flammable gas is formed. Write the equation.

45. Acetylene is called carbide gas. Explain the reason.

46. Write the equation of the reaction between CH2CHCH2CH3 and H2O(g).

47. When ethene is added to alkaline KMnO4 at room temperature, it is oxidized. Write the equation.

48. If an excess of MnO4- in an acid solution is added to CH2CH2, what is the product? Write the equation.

49. Ethene undergoes addition polymerization. Write the equation.

50. What is the major result of the elimination reaction of ethanol? Write the equation.

51. If 1-pronanol is added by sulfuric acid at 180ºC, the main product is ….a. Propaneb. propunec. propened. 2-propanole. Propilsulphate

52. When 1-butanol is added by sulfuric acid at 180ºC , what is the major product? Write the equation.

53. Propylchloride reacts with potassium hydroxide in alcohol. What is the major product? Write the equation.

54. Butylbromide reacts with potassium hydroxide in alcohol. Write the equation.

55. What reagents would you need to change hexylchloride become 1-hexene?

56. Write the above equation.

57. What reagents would you need to prepare 3-bromo-2-pentanol?

58. Write the above equation.

59. Which reactant could be dehydrohalogenated to give 2-butyne?

60. Write the above equation.

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