2nd Year Chemistry Chapter 10 Alkyl Halides Notes MCQs Short Questions Solution

chemistry 12th notes chapter No 10

1. Reaction of C₂H₅MgBr with CO₂ is an example of:


2. Butane nitrile is formed by reaction of KCₙ with:


3. The alkyl halide is converted into an alcohol directly by:


4. SN² reaction can be best carried out with:


5. Primary alcohol is obtained by treating Grignard’s Regent with:


6. Tetrabomoethane on treatment with alcoholic zinc gives:


7. For the reaction C₂H₅OH+ HX → C₂H₅-X + H₂O the order of reactivity of HX is:


8. Tertiary alcohols are obtained by treating Grignard’s reagent with:


9. Thionyl chloride reacts with alcohol to form:


10. 1-bromobutane on reaction with alcoholic potassium hydroxide gives:


11. Carbanions are:


12. Ethyl bromide when reduced with nascent hydrogen the product will be:


13. In β-elimination reaction, nucleophile attacks on:


14. In primary alkyl halides, the halogen atom is attached to a carbon which is further attached to:


15. Elimination bimolecular reaction involves:


16. Which of the following factors does not affect the SN¹ rate is:


17. For which mechanism the first step involved is the same:


18. When Grignard reagent reacts with Epoxide, it forms:


19. When bromomethane is hydrolyzed by aqueous NaOH solution which ion  brings about the first stage of substitution:


20. Which of the following reactions is not shown by an alkyl halide:


21. Alkyl magnesium halide (Grignard’s reagent) when hydrolyzed yields:


22. Ethyl magnesium bromide reacts with water to form:


23. In unimolecular reactions, the reaction completes in:


24. Which of the following reagent cannot be used for preparing alkyl chloride from alcohol:


25. Which of the following is not a Nulceophile?


26. In the transition state of SN² mechanism reaction with alkhyl halides, which  of the following orbital hybridization is involved:


27. Electrophile among the following is:


28. Which of the following is a Sodium Lead alloy:


29. Which responds positively towards Iodoform test:


30. Tertiary alcohol is obtained by treating Grignard reagent with:


31. Secondary alcohol is formed when Grignard’s reagent reacts with:


32. Which substance is used to convert alcohol to alkyl halide:


33. Which one of the following is not associated with SN² mechanism:


34. Which of the following alkyl halide is the most reactive towards the attacking  nucleophile:


35. SN² mechanism involves:


36. SN¹ reaction of Alkyl halides leads to:


37. Which of the following does not give Iodoform test:


38. Which of the following is not a nulceophile:


39. The reaction of an Alkyl halide with RCOOAg produces:


40. Which one of the following will have the maximum dipole moment:


41. Ethyl chloride reacts with alcoholic KOH to give:


42. Secondary alkyl halides follow


43. Carbocation is a/an:


44. Acetic acid can be obtained from CH₃MgI by treatment with:


45. 1, 3 – Dibromopropane reacts with metallic zinc to form:


46. In which two mechanisms, the first step involved is same:


47. Grignard’s reagent reacts to form alkane with:


48. (CH₃)₃CBr preferably undergoes:


49. SN² reactions are:


50. When an alcohol reacts with SOCl₂ an alkyl halide is formed what are two other products:


51. Order and molecularity of SN² reaction of alkyl halide is:


52. Ethyl alcohol gives Ethyl chloride with the help of:


53. Carbon atom holding halogen in Alkyl halide is:


54. SN¹ reactions are easily given by:


55. Alkyl Halides are:


56. In SN² mechanism, the hybridization of carbon atom changes from:


57. Grignard reagent is reactive due to:


58. Most reactive Alkyl halide towards SN¹ reaction is:


59. Iodoethane reacts with sodium in ether, the product formed is:


60. Reaction of following with Grignard’s reagent can give primary alcohol:


61. The order of a typical SN² reaction is:


62. Which one of the following is not a nucleophile:


63. The substances which donates a pair of electron to electrophile are called:


64. C-X bond is strongest in:


65. Which substance is used to convert Grignard’s reagent to alkane:


66. The order of a typical SN² reaction is:


Short Questions

1. Convert ethanol to get their respective halides by using PCI₃ and PI₅?
“2. Define and give one example of each.
i) Nucleophile ii) Leaving group?”
3. Explain the order of reactivity of alkyl halides on the basis of bond polarity.
4. Explain the structure and reactivity of Grignard’s reagent.
5. Give the general pattern of reaction of SN¹ mechanism.Why tertiary alkyl halides give this mechanism?
6. Give the general pattern of the reaction of SN²-mexhanism.What is its rate expression?Give examples?
7. Give the mechanism for the addition of Grignard’s reagent at CO₂ ti give carboxylic acids?
8. Give the mechanism for the reaction of formaldehyde with ethyl magnesium bromide?
9. How alkyl halides can be prepared by alcohols? Give two examples.
10. How antiknocking agents are prepared?
11. How compounds with active – H react with G.R to give alkanes?
12. How do we get alkyl nitriles from Grignard’s reagent?
13. How do we get alkyl nitrles from Grignard’s reagent?
14. How do you compare SN¹ and SN² mechanism?
15. How Grignard reagent reacts with epoxides to form alcohol?
16. How is carboxylic acid prepared from Grignard’s reagent?
17. How primary alcohols are produced when ethene epoxide is reacted with Grignard’s reagent?
18. How tetraethyl lead can be prepared from an alkyl halide?
19. How the bond dissociation energy of carbon suggests that alkyl iodides should have maximum reactivity?
20. How the nature of alkyl group changes when alkyl halide is converted to grignanr’s reagent?
21. In tertiary alkyl halides, SN¹ reaction takes place but not SN² reaction. Why?
22. Show the mechanism for the reaction of acetone with Grignard’s reagent?
23. SOCI₂ is the best reagent to get alkyl halides from alcohols.Which solvent is necessary to complete this reaction?
24. What are alkyl halides?Give their general formula and name two monohaloalkanes?
25. What are differences between SN¹ and SN² reactions?
26. What are leaving group and substrate?
27. What are primary and tertiary alkyl halides? Give one example of each.
28. What are primary secondary and tertiary alkyl halides?Give example of each?
29. What are the mecessary conditions to convert alcohols into alkyl halides by using halogen acids?
30. What is an excellent method to prepare alkyl halides?
31. What is difference between Electrophile and Nucleophile?
32. What is difference between Elimination and substitution reactions?
33. What is difference between molecularity and order of reaction?
34. What is Grignard’s reagent? Why dry ether is necessary for the preparation of Grignard’s reagent?
35. What is meant by attacking nucleophile? Give examples.
36. What is the mechanism for the reaction of Grignard’s reagent with acetaldehyde?
37. What is the nature of C-Mg bond in R-Mg-X?
38. What is the order of reactivity of HX with Ethene?
39. What is the role of Carbonium ion for determining SN¹ or SN² mechanism?
40. What is the role of stability of carbonium ion for determining SN¹ or SN² mechanism?
41. What is the role of steric hinderance to decide about SN¹ and SN² mechanisms?
42. What is Wurtz’s synthesis reaction?
43. Which two factors are responsible for reactivity of alkyl halides as compared to alknes?
44. Why tertiary alkyl halides follow SN¹ mechanism and not SN² mechanism?
“45. Write down reactions of ethanol with
(i) PBr₃ (ii) PCl₅”

Long Questions

1. Define Alkyl Halide. Give three methods to prepare them from Alcohols.
“2. Complete the following chemical reactions.
(i) CH₃ CH₂Cl + Na ——->
(ii) CH₃-CH₂-OH+ SOCI₂ ——->
(iii) CH₃-CH₂ – Cl + Na₄Pb ——->
(iv) CH₃ – CH₂ – CI+ KOH(aq) ——->”
3. Discuss reactivity of alkyl halides.
4. Discuss two main factors which govern reactivity of halides.
“5. Write note on the following terms and give an example in each case.
(i) Substrate (ii) Nucleophile (iii) Electrophile (iv)Leaving group”
6. What are SN-reactions? Explain SN¹ reaction in detail.
7. What are SN reaction? Differentiate between SN¹ and SN² reaction?
8. Discuss SN² reactions of alkyl halides in detail.
9. Write a note on SN¹ reactions.
10. Define Nucleophilic substitution reactions and discuss the mechanism of SN¹ reactions
11. What are SN reactions & Explain SN¹ reactions with help of suitable example.
“12. Using ethyl bromine how would you prepare
n-Butane, ethene”
13. Define elimination reactions and discuss the mechanism of E2 reactions.
14. Write a note on β-elimination reactions.
“15. Using ethyl bromide as a starting material how would you prepare:
(i) n-butane (ii) Ethene iii) Ethyl Alcohol (iv) Propanic acid”
16. Discuss briefly the two possible mechanisms of β-elimination reactions.
17. Compare E2 and E1 mechanism for the β-Elimination reactions?
18. Write down reaction of CH₃-CH₂-CI with (i) Na (ii) Zn + HCI (iii) Na₄Pb(iv) Mg
“19. Write the reactions of the Grignard reagent with the following:
(i) Water (ii) Ammonia (iii) CO₂ (iv) Alcohol”
20. How would Grignard reagent reacts with the following: i) Acetaldehyde ii) Acetone iii) Cyanogen Chloride iv) Alcohols
“21. What products are formed when the following compounds are treated with ethyl magnesium bromide followed by hydrolysis in the presence of an acid
(i) HCHO (ii) CH₂CHO (iii) (CH₃)₂CO (iv) CICₙ”
22. Give reactions of ethyl magnesium bromide with (i) HCHO (iii) CH₃CHO (iii) (CH₃)₂CO (iv) Cl
“23. Give reaction of Grignard’s reagent with
(i) Alcohol (ii) CO₂ (iii) Acetaldehyde.”
“24. What products are formed when the following compounds are treated with ethyl magnesium bromide, followed by hydrolysis in the presence of an acid?
(i) Fromaldehyde (ii) CO₂ (iii) Acetaldehyde (iv) Ethyl alcohol”
“25. How will you make the following conversions:
(i) Acetic acid into propanoic acid
(ii) Acetone into teriary butyl alcohol”
“26. What is β-Elimination reaction? Differentiate between E1 and E2 elimination reactions. How does ethanol react with
(i) Na (ii) PCI₅ (iii) CH₃MgI (iv) SOCI₂”
27. What are Nucleophilic substitution reactions? Explain s² mechanism.
28. What is β- Elimination Reaction? Explain E1 reaction in detail.
29. Write note on the following (i) Classification of Alkyl halides (ii) Wurtz Synthesis.

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