10. HALOALKANES AND HALOARENES Objective

10. HALOALKANES AND HALOARENES

1. Good conductor of electricity and heat is

(A) Anthracite coke
(B) Diamond
(C) Graphite
(D) Charcoal

2. In which of the following allotropes of carbon, percentage of carbon is maximum ?

(A) Wood charcoal
(B) Coconut charcoal
(C) Graphite
(D) None of these

3. The hybridisation of carbon in diamond is

(A) sp³
(B) sp²
(c) sp
(D) dsp²

4. Organic compound must contain an element

(A) oxygen
(B) carbon
(C) hydrogen
(D) nitrogen

5. Alkene gives which of the following reactions ?

(A) Addition reaction
(B) Substitution reaction
(C) Both (A) and (B)
(D) None of these

6. Single bond length between carbon-carbon is

(A) 1.34 Å
(B) 1.20 Å
(C) 1.54 Å
(D) none of these

7. Valency of carbon is

(A) 1
(B) 2
(C) 3
(D) 4

8. Criteria for purity of organic solid is

(A) boiling point
(B) melting point
(C) specific gravity
(D) none of these

9. General formula of Alkene is

(A) C_nH_2n
(B) C_nH_{2n + 2}
(C) C_nH_{2n – 2}
(D) none of these

10. Hybridisation of carbon in ethane is

(A) sp³
(B) sp²
(C) sp
(D) sp³d²

11. Number of π bonds in ethyne is

(A) 1
(B) 2
(C) 3
(D) 4

12. The compound having general formula C_nH_{2n + 2} is

(A) Alkene
(B) Alkyne
(C) Alkane
(D) none of these

13. The antiseptic action of CHI₃ is

(A) due to idoform
(B) due to liberation of free iodine
(C) partially due to iodine and partially due to CHI₃
(D) none of these

14. Which of the following is not correctly matched with its IUPAC name ?

(A) CHF₂ CBrCIF : 1-Bromo- 1 -chloro- 1, 2, 2- trifluoroethane
(B) (CCl₃)₃CCl : 2-(Trichloromethyl)-1, 1, 2, 3, 3- heptachloropropane
(C) CH₃C (p-ClC₆H₄)₂ CH(Br)CH₃ : 2-Bromo-3, 3-bis (4-chlorophenyl) butane
(D) o-BrC₆H₄CH (CH₃) CH₂CH₃ : 2-Bromo-1- methylpropylbenzene

15. The reaction

CH2 = CH – CH₃ + HBr → ₃– CH-CH₃ is an example of

(A) nucleophilic addition
(B) free radical addition
(C) electrophilic addition
(D) electrophilic substitution

^16.

X and Y in the reaction are

17. Which one of the following is not correct order of boiling points of the alkyl/aryl halides ?

(A) CHCl₃ > CH₂Cl₂
(B) CH₃(CH₂)₃Cl > CH₃(CH₂)₂Cl
(C) (CH₃)₃CCl > (CH₃)₂ CHCH₂Cl
(D) CH₃(CH₂)₃Cl > CH₃CH CHClCH₃

18. Which of the following compounds will have highest melting point ?

(A) Chlorobenzene
(B) o-Dichlorobenzene
(C) m-Dichlorobenzene
(D) p-Dichlorobenzene

19. Ethyl alcohol is obtained when ethyl chloride is boiled with

(A) alcoholic KOH
(B) aqueous KOH
(C) water
(D) aqueous KMnO₄

20. Which of the following alkyl halides undergoes hydrolysis with aqueous KOH at the fastest rate ?

(A) CH₃CH₂CH₂Cl
(B) CH₃CH₂Cl
(C) CH₃CH₂CH₂CH₂Cl
(D) CH₃CH₂CH (Br) CH₃

21. The alkyl halide is converted into an alcohol by

(A) elimination
(B) dehydrohalogenation
(C) addition
(D) substitution

22. A mixture of 1-chloropropane and 2- chloropropane when treated with alcoholic KOH gives

(A) prop-1-ene
(B) prop-2-ene
(C) a mixture of prop-1-ene and prop-2-ene
(D) propanol

23. Arrange the following alkyl halides in order of dehydrohalogenation

C₂H₅I, C₂H₅ Cl, C₂H₅Br, C₂H₅F

(A) C₂H₅H > C₂H₂Cl > C₂H₅Br > C₂H₂I
(B) C₂H₅I > C₂H₅Br > C₂H₅Cl > C₂H₅F
(C) C₂H₅I > C₂H₅Cl > C₂H₅Br > C₂H₅F
(D) C₂H₅F > C₂H₅I > C₂H₅Br > C₂H₅Cl

24. Tertiary alkyi halides are practically inert to substitution by S _N2 mechanism because

(A) the carbocation formed is unstable
(B) there is steric hindrance
(C) there is inductive effect
(D) the rate of reaction is faster in S _N² mechanism

25. The order of reactivity of following alcohols with halogen acids is

I. CH3CH2 – CH2 – OH II. CH3CH2 CH – OH
.                                                                   

(A) I > II > III
(B) III > II > I
(C) II > I > III
(D) I > III > II

26. Identify the compound ‘Y’ in the following reaction :

27. Arrange the following compounds in the increasing order of their densities

(A) I < II < III < IV
(B) I < III < IV < II
(C) IV < III < II < I
(D) II < IV < III < I

28. Arrange the following compounds in increasing order of their boiling point

I. CH – CH2Br             II. CH3CH2CH2CH2Br

(A) II < I < III
(B) I < II < III
(C) III < I < II
(D) III < II <I

29. A primary alkyl halide would prefer to undergo

(A) S_N1 reaction
(B) S_N2 reaction
(C) α-elimination
(D) racemisation

30. Reaction of C₆H₅CH₂Br with aqueous sodium hydroxide follows

(A) S_N1 mechanism
(B) S_N2 mechanism
(C) Any of the above two depending upon the temperature of reaction
(D) Saytzeff rule

31. Which of the following compounds will give racemic mixture on nucleophilic substitution by OH-ion ?

(A) I
(B) I, II, III
(C) II, III
(D) I, III

32. A Grignard reagent is prepared by the action of magnesium in dry ether on ?

(A) C₂H₅OH
(B) C₂H₆
(C) C₂H₅Cl
(D) C₂H₅CN

33. Primary, Secondary and Tertiary alcohols are distinguished by

(A) Oxidation method
(B) Lucas reagent method
(C) Victor Meyer’s method
(D) All of these

34. Ethyl acetate reacts with CH2MgBr to from

(A) Secondary alcohol
(B) Tertiary alcohol
(C) Primary alcohol and Acid
(D) Carboxylic acid

Class 12th Chemistry Objective Question English