1. Alkanes are saturated hydrocarbons and therefore, are generally ….
c. quite reactive
d. more reactive than alkenes
e. less reactive than alkenes
2. Alkanes are saturated hydrocarbons. The following statements are correct about alkanes, except ….
a. generally reactive
b. the molecules are non-polar
c. the general formulae is CnH2n+2
d. unreactive towards polar or ionic reagents
e. react with Br2 only in the presence of UV light
3. Alkanes are non-polar and so, are unreactive towards ….
a. non-polar reagens
b. ionic reagents
e. hydrogen halides
4. Which of the following statements is NOT correct regarding the reactivity of alkanes?
a. Alkanes are generally inert.
b. Alkanes react with acids and bases.
c. Alkanes are often used as solvents for chemical reactions.
d. Alkanes react with halogens and oxygen upon ignition.
5. Which of the following statements about alkanes is not correct?
a. Alkanes contain only strong sigma bonds.
b. Alkanes do not contain any double or triple bonds.
c. The electronegativities of C and H are about the same, so C-H bonds have no significant polarity.
d. The electronegativities of C and H differ greatly; the H is the negative pole of the bond.
6. All hydrocarbons burn easily in an excess oxygens to form carbon dioxide and water. This reaction is classified as ….
c. incomplete burning
d. complete combustion
e. incomplete combustion
7. All hydrocarbons burn easily in an excess of O2 to give carbon dioxide and water. The large negative ∆H’s (exothermic reactions) explain why hydrocarbons are useful as fuels. When hydrocarbons burn in a limited supply of air (O2), the products is (are) ….
a. carbon dioxide
b. carbon monoxide and carbon
c. carbon monoxide, carbon, and water
d. carbon dioxide and carbon monoxide
e. carbon dioxide, carbon monoxide, carbon and water V
8. The large negative ∆H’s explain why hydro-carbons are useful as fuels. The following properties that unrelated to the above information is ….
b. release energy
c. can produce fire
d. react with oxygen
e. easily to be burned
9. The correct chemical equation of complete combustion in general is ….
a. CxHy + O2 CO + H2O
b. CxHy + O2 CO2 + H2O
c. CxHy + O2 x CO2 + y/2 H2O
d. CxHy + (x+y) O2 x CO + y H2O
e. CxHy + (x+y/4) O2 x CO2 + y/2 H2O
10. Hydrocarbons only burn in the gaseous state. The meaning of this statement is ….
a. solid hydrocarbons can not be burned
b. liquid hydrocarbons are difficult to be burned
c. in the gaseous state, the number of molecules decrease
d. each molecule of hydrocarbons gas is far one of another
e. the molecule is easily reacting, because its mass decreases
11. The following statements which correct about burning hydrocarbons is ….
a. less volatile hydrocarbons burn less readily
b. solid hydrocarbons must be vaporized before burning
c. CO and C are also formed in an incomplete combustion
d. for completing combustion, an excess oxygen is needed
e. when hydrocarbons burn in a limited oxygen, still produce CO2
12. The products of the balanced equation for the combustion of propane are ….
a. 2CO2 + 4H2O
b. 3CO + 4H2O
c. 3CO2 + 4H2O
13. Balance the following combustion reaction of hexane by supplying the correct coefficient in front of the other three species.
C6H14 + __O2 __CO2 + __H2O
What is the coefficient in front of O2?
14. The balanced equation for the combustion of pentane is ….
a. C3H8 + 5 O2 → 3 CO2 + 4 H2O
b. C5H12 + 8 O2 → 5 CO2 + 6 H2O
c. 2 C3H8 + O2 → 3 CH4 + 2 H2O
d. 2 C5H12 + 2 O2 → 10 CH4 + 2 H2O
e. 4 C5H12 + 2 O2 → 20 CH4 + 4 H2O
15. What are the products of the combustion of 4-methyl-2-hexene?
a. Smaller hydrocarbons
b. CH4 and H2O
c. CO2 and H2O
d. C and H2O
16. The reaction of alkanes with halogens is called ….
17. A substitution reaction is a reaction in which a part of the reagent molecule is substituted for … on a hydrocarbon or hydrocarbon group.
a. H atom
b. O atom
c. Cl atom
d. H2 molecule
e. Cl2 molecule
18. All of the H atoms of an alkane may undergo substitution, leading to a mixture of products. The correct answer is ….
a. bromine is the most reactive reagent
b. chlorine is more reactive than fluorine
c. bromine is more reactive than chlorine
d. fluorine is very reactive, usually gives complete substitution
e. chlorine is less reactive than bromine, often requires elevated temperatures
19. What relative amounts of 1-bromo butane and 2-bromobutane are actually formed when butane is brominated?
a. 1-bromobutane : 2-bromobutane = 1 : 55
b. 1-bromobutane : 2-bromobutane = 55 : 1
c. 1-bromobutane : 2-bromobutane = 1 : 25
d. 1-bromobutane : 2-bromobutane = 25 : 1
e. 1-bromobutane : 2-bromobutane = 3 : 2
20. What is the major product obtained from the monobromination of 2-methylbutane in the presence of light at room temperature?
21. What is the major product obtained from the monochlorination of 2-methylbutane in the presence of light at room temperature?
22. Alkanes react with the halogens via free-radical substitution reaction in the presence of sunlight. When methane reacts with chlorine in sunlight, so ….
a. a chain reaction is may not be occurred
b. a carbon tetrachloride is the main product
c. one or more chlorine atoms may replease hydrogen atoms
d. the products do not depend on the amounts of halogen and alkane
e. the yellowish-green colour of Cl2 fades and HCl(g) can be detected
23. The wrong information about a chain reaction of a substitution is ….
a. the mechanism consists of four steps
b. the slow step reaction is the formation of free radical
c. the reaction does not proceed in the dark at room temperature
d. in the propagation, the free radicals attact the alkane molecules
e. the chain reaction is terminated when two free radicals combine
24. From the following mechanism, the termination equation is ….
a. Cl2 Cl* + Cl*
b. Cl* + CH4 CH3* + HCl
c. CH3* + Cl2 CH3Cl + Cl*
d. CH3* + CH2Cl* CH3CH2Cl
e. Cl* + CH3Cl CH2Cl* + HCl
25. Alkenes are more reactive than alkanes because of the presence of ….
a. the single bond
b. the double bond
c. the triple bond
d. the carbon atoms
e. the hydrogen atoms
26. An addition reaction is a reaction in which parts of a reactant are added to each carbon atom of a carbon–carbon double bond, which then ….
a. has enough carbon atoms
b. the length of the chain increases
c. the atoms of hydrogen increase
d. becomes a carbon–carbon single bond
e. the number of carbon-carbon double bond decrease
27. Addition to triple bonds is also possible, giving a product with ….
a. a single bond
b. a single bond and a double bond
c. a single bond, if there is an excess reactant
d. a double bond, if there is an excess reactant
e. a triple bond, if there is not enough reactant
28. The product of the hydrogenation of 2-butene is ….
29. The addition of Br2 to an alkene is ….
a. very slow
b. very fast
c. faster than Cl2
d. slower than Cl2
e. quite slow
30. With which of the following would you expect to observe a color change when it was mixed with bromine water?
31. 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. When a few drops of the solution are added to an alkene, so ….
a. the bromine immediately react
b. the color of bromine changes
c. the reaction occurs suddently
d. the redbrown color of the bromine changes
e. the redbrown color of the bromine is immediately lost
32. The addition of Br2 to cyclohexene gives ….
33. The addition of hydrogen to 3-methyl cyclopentene gives the product named ….
34. The addition of Cl2 to 4-methyl-2-pentene gives the product named ….
b. 3, 4-dichloro-2-methylpentane
c. 3, 4-dichloro-2-methylpentene
d. 2, 3- dichloro-4-methylpentane
e. 2, 3- dichloro-4-methylpentene
35. Complete the following equation:
C3H6 + Br2
The product is ....
c. C3H5Br + HBr
d. CH3Br + C2H3Br
e. no reaction
36. If an excess of Br2 is added to CH ≡ CH, the correct product is ….
37. The following statements are correct about an addition reaction, except ….
a. HCl and HBr are unsymmetrical reagents
b. 1-butene is an unsymmetrical alkene
c. two products that are isomers will occurred in equal amounts v
d. the H atom of HBr adds to C atom 1, giving 2-bromopropane
e. the H atom of HBr adds to C atom 2, giving 1-bromopropane
38. The correct statement about the Markownikoff’s rule is ….
a. the richer gets rich
b. there is only one product formed
c. HBr is a symmetrical reagents
d. H2O could not be added to alkenes
e. H atom of HCl attacts C atom of C = C
39. The main product when HBr adds to 1-butene is ….
40. The addition of HCl to 2-methyl-2-butene follows Markovnikov's Rule. The product is ….
41. The alkynes also undergo addition reactions, usually adding … molecule(s) of the reagent for each C ≡ C bond.
42. If an excess of HCl is added to CH3C≡CH, the product is ….
43. The product of addition of excess bromine to 2-butyne is ….
44. When calcium carbide is added to water, a flammable gas is formed. The gas is
a. carbon dioxide
45. The reaction between CH2CHCH3 and H2O(g) will produce ….
46. When ethene is added to alkaline KMnO4 at room temperature, it is oxidized to give ….
47. If an excess of MnO4- in an acid solution is added to CH2CH2, the product is ….
c. C and H2O
d. CO and H2O
e. CO2 and H2O
48. Ethene undergoes addition polymerization to give ….
49. The major result of the elimination reaction of ethanol is ….
50. If 1-pronanol is added by sulfuric acid at 180ºC, the main product is ….
51. When 1-butanol is added by sulfuric acid at 180ºC , the major product is ….
52. Propylchloride reacts with potassium hydroxide in alcohol. The major product is ….
53. Butylbromide reacts with potassium hydroxide in alcohol. The main product is ….
54. What reagents would you need to change butilchloride become 1-butene?
c. KOH + C2H5OH
55. What reagents would you need to prepare 3-bromo-2-butanol?
a. 2-butene and HBr
b. 1-butene, Br2, and water
c. 1-butene, HBr, and water
d. 2-butene, HBr, and water
e. 2-butene, Br2, and water
56. Which of the following could be dehydrohalogenated to give 2-butyne?