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Haloalkanes and Haloarenes - ISC Class 12 Chemistry Questions with Answers, Page 2

47 past-paper questions on Haloalkanes and Haloarenes from ISC Class 12 Chemistry papers (2027-2018), newest first, in full. Questions 21-40 are on this page, 20 to a page. Tap "Show answer" under a question to see its answer.

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2025 · 1 mark · MCQOpen: Rahul wants to prepare chloroform in the laboratory using ethanol. The correct…
Rahul wants to prepare chloroform in the laboratory using ethanol. The correct order of preparation is:
  • (a)oxidation, liberation of $\text{Cl}_2$, hydrolysis and chlorination.
  • (b)liberation of $\text{Cl}_2$, oxidation, chlorination, hydrolysis.
  • (c)hydrolysis, oxidation, chlorination, liberation of chlorine.
  • (d)chlorination, hydrolysis, oxidation, liberation of chlorine.

No answer yet.

2025 · 1 mark · Assertion-reasonOpen: The use of phosphorus chlorides is preferred to thionyl chloride in the…

Assertion: The use of phosphorus chlorides is preferred to thionyl chloride in the preparation of alkyl chlorides from alcohol.

Reason: Phosphorous chlorides give pure alkyl chlorides.

Given below are two statements marked Assertion and Reason. Read the two statements carefully and select the correct option.
  • (a)Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
  • (b)Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.
  • (c)Assertion is true and Reason is false.
  • (d)Both Assertion and Reason are false.

No answer yet.

2025 · 2 marks · Short answerOpen: Given below are the two types of mechanism of the reaction: Answer the…
Given below are the two types of mechanism of the reaction: Answer the following questions:
Figure for this question
(a)
Why is the product obtained in (A) pathway optically inactive?
(b)
Investigate the effect of plane polarised light on the product of (B) pathway? Which pathway shows faster reaction?

No answer yet.

2025 · 1 mark · Assertion-reasonOpen: Electrophilic substitution reactions in haloarenes takes place in ortho and…

Assertion: Electrophilic substitution reactions in haloarenes takes place in ortho and para positions and the major product is para substituted haloarenes.

Reason: The halogen in the ring is not ortho and para directing, and the yield is more of para because of resonance stabilisation.

  • (a)Both Assertion (A) and Reason (R) are correct, and Reason (R) is the correct explanation of the Assertion (A).
  • (b)Both Assertion (A) and Reason (R) are correct, and Reason (R) is not the correct explanation of the Assertion (A).
  • (c)Assertion (A) is true, but Reason (R) is false.
  • (d)Assertion (A) is false, but Reason (R) is true.

No answer yet.

2025 · 3 marks · Short answerOpen: Chloroform was synthesised in the year 1847. It was mainly used in the medicine…
Chloroform was synthesised in the year 1847. It was mainly used in the medicine industry. When exposed to sunlight it forms a poisonous gas called phosgene. To prevent this, a small quantity of a compound which has a molecular formula $\text{C}_2\text{H}_6\text{O}$ is added.
(a)
What is the chemical formula of phosgene?
(b)
Which chemical is added to prevent the formation of phosgene.
(c)
Where is chloroform used in the field of medicine?

No answer yet.

2025 · 1 mark · Assertion-reasonOpen: Tertiary butyl bromide undergoes Wurtz reaction to give…

Assertion: Tertiary butyl bromide undergoes Wurtz reaction to give 2,2,3,3-tetramethylbutane.

Reason: In Wurtz reaction, when same alkyl halides react with sodium in dry ether to give hydrocarbon; the hydrocarbon formed contains double the number of carbon atoms present in the alkyl halide.

Given below are two statements marked Assertion and Reason. Read the two statements carefully and select the correct option.
  • (a)Both Assertion and Reason are true and Reason is the correct explanation of assertion.
  • (b)Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.
  • (c)Assertion is true but Reason is false.
  • (d)Both Assertion and Reason are false.

No answer yet.

2024 · 1 mark · Fill inOpen: Fill in the blanks by choosing the appropriate word(s) from those given in the…
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets: [decreases, $\text{CN}^-$ ion, activation energy, catalyst, two, $\text{Fe}^{2+}$ ion, carbon, lattice energy, enzyme, five, double, halogen, triple, increases] Haloalkenes undergo both nucleophilic and electrophilic reactions due to the presence of ____ bond and the ____ atom.

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2024 · 1 mark · Fill inOpen: Choose the appropriate word(s) from the bracket [lead poisoning, zero…
Choose the appropriate word(s) from the bracket [lead poisoning, zero, phosgene, dependent, cancer, independent, diethyl ether, first, ethyl carbonate, ethene]: The addition of small quantity of ethanol to chloroform prevents the formation of ____ and converts it into the harmless compound ____.

No answer yet.

2023 · 2 marks · Short answerOpen: Question
(i)[1.0]

Assertion: Specific conductance of all electrolytes decreases on dilution.

Reason: On dilution, number of ions per unit volume decreases.

  • (a)Both assertion and reason are true and reason is the correct explanation of assertion.
  • (b)Both assertion and reason are true but reason is not the correct explanation for assertion.
  • (c)Assertion is true but reason is false.
  • (d)Assertion is false but reason is true.
(ii)[1.0]

Assertion: Nitration of chlorobenzene leads to the formation of m-nitro chlorobenzene.

Reason: Nitro ($-\text{NO}_2$) group is a m-directing group.

  • (a)Both assertion and reason are true and reason is the correct explanation of assertion.
  • (b)Both assertion and reason are true but reason is not the correct explanation for assertion.
  • (c)Assertion is true but reason is false.
  • (d)Assertion is false but reason is true.

No answer yet.

2023 · 2 marks · Short answerOpen: Identify compounds [A] and [B] in the following reactions.
Identify compounds [A] and [B] in the following reactions.
(i)[1.0]
$\text{CH}_3\text{Br} + \text{KCN (alc)} \longrightarrow [\text{A}] \xrightarrow[\text{(complete hydrolysis)}]{+\text{HOH}/\text{H}^+} [\text{B}]$
(ii)[1.0]
$\text{C}_6\text{H}_5\text{NH}_2 + \text{HNO}_2 + \text{HCl} \xrightarrow{0\text{--}5^\circ\text{C}} [\text{A}] \xrightarrow{\text{Cu}_2\text{Cl}_2/\text{HCl}} [\text{B}]$

No answer yet.

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