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Class 12 Chemistry  MCQ Questions of Haloalkanes and Haloarenes with Answers?

Answer 1

  Students can solve NCERT Class 12 Chemistry Haloalkanes and Haloarenes MCQ Questions with Answers to realize their level of preparation for exams. CBSE Chemistry Class 12 Chemistry MCQ Questions of Haloalkanes and Haloarenes with Answers. MCQ Questions for Class 12 Chemistry Chapter Wise with Answers was Prepared Based on Latest Exam Pattern and Syllabus.

Given underneath are MCQ Questions for class 12 which will help you with analyzes your knowledge on the topics. The appropriate responses are likewise accommodated reference.

Practice MCQ Question for Class 12 Chemistry chapter-wise

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. Criteria for purity of organic solid is

(a) boiling point
(b) melting point
(c) specific gravity
(d) none of these 

4. The negative part of the addendum (the molecule to be added) adds on the carbon atom of the double bond containing the least number of hydrogen atoms. This rule is known as

(a) Saytzeffs rule
(b) Peroxide rule
(c) Markovnikov’s rule
(d) van’t hoff rule

5. Which of the following compounds can yield only one monochlorinated product upon free radical chlorination?

(a) 2, 2-Dimethylpropane
(b) 2-Methylpropane
(c) 2-Methylbutane
(d) n-Butane

6. Bromination of methane in presence of sunlight is a

(a) nucleophilic substitution
(b) free radical substitution
(c) electrophilic substitution
(d) nucleophilic addition

7. Which of the following reactions follows Markovnikov’s rule?

(a) C₂H₄ + HBr
(b) C₃H₆ + Cl₆
(c) C₃H₆ + HBr
(d) C₃H₆ + Br₂ 

8.  Which of the following compounds has the highest boiling point?

(a)CH₃CH₂CH₂Cl
(b) CH₃CH₂CH₂CH₂Cl
(c) CH₃CH(CH₃)CH₂Cl
(d) (CH₃)₃CCl

9. Alkyl halides are immiscible in water though they are polar because

(a) they react with water to give alcohols
(b) they cannot form hydrogen bonds with water
(c) C -X bond cannot be broken easily
(d) they are stable compounds and are not reactive

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

(a) Chlorobenzene
(b) o-Dichlorobenzene
(c) m-Dichlorobenzene
(d) p-Dichlorobenzene

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

(a) alcoholic KOH
(b) aqueous KOH
(c) water
(d) aqueous KMnO₄

12. The end product (Q) is in the following sequence of reaction

13. Methyl bromide reacts with AgF to give methyl fluoride and silver bromide. This reaction is called

(a) Fittig reaction
(b) Swarts reaction
(c) Wurtz reaction
(d) Finkelstein reaction

14. The alkyl halide is converted into an alcohol by

(a) elimination
(b) dehydrohalogenation
(c) addition
(d) substitution

15. Grignard reagents are formed by the reaction of alkyl halides by warming

(a) with alcoholic solution
(b) with MgCl₂
(c) Mg in presence of dry ether
(d) with MgCO₃

16. The pesticide DDT slowly changes to

(a) CCl₃ -CHO and chlorobenzene
(b) p, p'-Dichlorodiphenylethene
(c) p, p'-Dichlorodiphenyldichloroethane
(d) p, p'-Dichlorodiphenyldichloroethene

17.  Rectified spirit is a mixture of

(a) 95% ethyl alcohol + 5% water
(b) 94% ethyl alcohol + 4.53 water
(c) 94.4% ethyl alcohol + 5.43% water
(d) 95.87% ethyl alcohol + 4.13% water

18. When two halogen atoms are attached to same carbon atom then it is :

(a) vic-dihalide
(b) gem-dihalide
(c) \(\alpha,\omega\) -halide
(d) \(\alpha,\beta\)  -halide

19.  How many structural isomers are possible for a compound with molecular formula C₃H₇Cl?

(a) 2
(b) 5
(c) 7
(d) 9

20. Phosgene is a common name for

(a) phosphoryl chloride
(b) thionyl chloride
(c) carbon dioxide and phosphine
(d) carbonyl chloride

21. The decreasing order of boiling points of alkyl halides is

(a) RF > RCl > RBr > RI
(b) RBr > RCl > RI > RF
(c) RI > RBr > RCl > RF
(d) RCl > RF > RI > RBr

22. Ethylene dichloride can be prepared by adding HCl to

(a) Ethane
(b) Ethylene
(c) Acetylene
(d) Ethylene glycol

23. The catalyst used in the preparation of an alkyl chloride by the action of dry HCl on an alcohol is

(a) anhydrous AlCl₃
(b) FeCl₃
(c) anhydrous ZnCl₂
(d) Cu

24. Which alkyl halide has maximum density?

(a) C₃H₇I
(b) C₂H₅I
(c) CH₃I
(d) CH₃Br

25. Ethyl bromide reacts with lead-sodium alloy to form:-

(a) tetraethyl lead
(b) tetraethyl bromide
(c) both (1) and (2)
(d) none of these

Answer 2

1. Answer : (c) Graphite

Explanation: In graphite, since pi-electrons are free to move throughout the entire layers so graphite is a good conductor of electricity. Its conductivity increases with temperature. because of these free electrons so it is also a good conductor of heat.

2.  Answer : (c) Graphite

Explanation: Graphite is an allotrope of carbon having a hexagonal structure. Under standard conditions, it is the most stable form of carbon. It contains about 90-95% of carbon.

3. Answer : (b) melting point

Explanation: Melting point is used as criteria for purity of solids. Pure solids will have sharp and fixed melting point. Impure solids have lower and variable melting point due to presence of impurity.

4. Answer : (c) Markovnikov’s rule

Explanation: According to the Markovnikovs rule, the negative part of the unsymmetrical reagent adds to less hydrogenated ( more substituted) carbon atom of the double bond. So here the negative part of the addendum gets attach to that carbon which possess lesser number of hydrogen atoms.

5. Answer : (a) 2, 2-Dimethylpropane

Explanation: All the hydrogen atoms in 2, 2-dimethyl - propane are equivalent, hence it can form only one monochlorinated product.

6. Answer : (b) free radical substitution

Explanation: A Free Radical Substitution Reaction: is a reaction between methane and bromine happens in the presence of ultraviolet light - typically sunlight. This is a good example of a photochemical reaction - a reaction brought about by light.

7. Answer : (c) C₃H₆ + HBr

Explanation: When HBr is added to an alkene in the absence of peroxides it obey Markovnikovs rule. When HBr reacts with unsymmetrical alkene in the presence of peroxides HBr adds in the opposite direction to that predicted by Markovnikov's rule.

CH₃CH = CH₂ + HBr

8.  Answer : (b) CH₃CH₂CH₂CH₂Cl

Explanation:CH₃CH₂CH₂CH₂Cl is butyl chloride. It is water white liquid with a sharp odor. It has the highest boiling point.

9. Answer : (b) they cannot form hydrogen bonds with water

Explanation: Water forms intermolecular hydrogen bonds which are strong interactions.Thus, alkyl halides can neither form hydrogen bonds nor can they break the hydrogen bonds of water. Thus, alkyl halides are immiscible in water though they are polar because they cannot form hydrogen bonds with water.

10. Answer : (d) p-Dichlorobenzene

Explanation: p - Dichlorobenzene is more symmetrical than the o- and m- isomers. So, it fits more closely in the crystal lattice. Therefore more energy is required to break the crystal lattice of p - dichlorobenzene. Therefore p - dichlorobenzene has highest melting point than the O- and m- isomers. It has melting point.

11. Answer : (b) aqueous KOH

Explanation: Ethyl chloride can undergo both nucleophilic substitution as well as elimination reactions with strong alkali like KOH. When it undergoes nucleophilic substitution, ethly alcohol is formed.

C₂H₅ + HCl(aq) → C₂H₅OH + KCl

12. Answer : 

Explanation: 

13. Answer : (b) Swarts reaction

Explanation: CH₃Br + AgF → CH₃F + AgBr. This reaction is known as Swarts reaction.

14. Answer : (d) substitution

Explanation: In a substitution reaction, the halogen atom is replaced by an -OH group to give an alcohol. For example: Or, as an ionic equation: In the example, 2-bromopropane is converted into propan-2-ol.

15. Answer : (c) Mg in presence of dry ether

Explanation: Grignard reagent are formed by the reaction of alkyl halides by warming Mg in the presence of dr ether.

16. Answer : (d) p, p'-Dichlorodiphenyldichloroethene

Explanation: DDT slowly changes to p, p'-Dichlorodiphenyldichloroethene. DDT stands for Dichloro diphenyl trichloroethane. It is an organochlorine compound and is an insecticide but it is known for its harmful impacts on the environment.

17. Answer : (d) 95.87% ethyl alcohol + 4.13% water

Explanation: Rectified spirit is a mixture with a composition of 95% ethanol and 5% water. To attain a pure form of absolute alcohol, one more separation step is required, so that the water content in rectified spirit is removed completely.

18. Answer : (b) gem-dihalide

Explanation: When two halogen atoms are attached to same carbon atom then it is called as geminal -dihalide .

19.  Answer : (a) 2

Explanation: Two isomers CH₃−CHCl−CH₃ and CH₃−CH₂−CH₂Cl are possible for C₃H₇Cl.

20. Answer : (d) carbonyl chloride

Explanation: Phosgene is a common name given to carbonyl chloride. It is used to manufacture organic chemicals, resins, dyes, plastics and pesticides.

21. Answer : (c) RI > RBr > RCl > RF

Explanation: As the size of halogen atom increases, boiling point of alkyl halides increases. Thus, the correct order of boiling point is RI > RBr > RCl > RF.

22. Answer : (d) Ethylene glycol

Explanation: Ethylene dichloride can be prepared by adding HCl to ethylene glycol (CH₂OH . CH₂OH).]

23. Answer : (c) anhydrous ZnCl₂

Explanation: OH group is converted into —Cl group by SOCl₂ or anhy. ZnCl₂/ conc. HCl or HCl etc.

24. Answer : (c) CH₃I

Explanation: The alkyl halide that has the highest density is methyl iodide (CH₃I) due to the lowest carbon content and a heavy halogen atom.

25. Answer : (a) tetraethyl lead

Explanation: Tetraethyl lead. Hint: When ethyl bromide is reacted with sodium lead alloy, it forms tetraethyl lead as major products with the elimination of sodium bromide as a byproduct.

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