back to directory
NEET CHEMISTRYHaloalkanes and HaloarenesEasy

Question

The products A and B obtained in the following reactions, respectively, are: 3ROH+PCl33RCl+A3\text{ROH} + \text{PCl}_3 \rightarrow 3\text{RCl} + \text{A} ROH+PCl5RCl+HCl+B\text{ROH} + \text{PCl}_5 \rightarrow \text{RCl} + \text{HCl} + \text{B}

A

POCl3\text{POCl}_3 and H3PO4\text{H}_3\text{PO}_4

B

H3PO4\text{H}_3\text{PO}_4 and POCl3\text{POCl}_3

C

H3PO3\text{H}_3\text{PO}_3 and POCl3\text{POCl}_3

D

POCl3\text{POCl}_3 and H3PO3\text{H}_3\text{PO}_3

Step-by-Step Solution

According to the methods of preparation of haloalkanes from alcohols:

  1. The reaction of an alcohol with phosphorus trichloride (PCl3\text{PCl}_3) yields an alkyl chloride along with phosphorous acid (H3PO3\text{H}_3\text{PO}_3). Therefore, product A is H3PO3\text{H}_3\text{PO}_3 . 3R-OH+PCl33R-Cl+H3PO33\text{R-OH} + \text{PCl}_3 \rightarrow 3\text{R-Cl} + \text{H}_3\text{PO}_3

  2. The reaction of an alcohol with phosphorus pentachloride (PCl5\text{PCl}_5) yields an alkyl chloride, phosphoryl chloride (POCl3\text{POCl}_3), and hydrogen chloride gas. Therefore, product B is POCl3\text{POCl}_3 . R-OH+PCl5R-Cl+POCl3+HCl\text{R-OH} + \text{PCl}_5 \rightarrow \text{R-Cl} + \text{POCl}_3 + \text{HCl}

Thus, A and B are H3PO3\text{H}_3\text{PO}_3 and POCl3\text{POCl}_3, respectively.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Haloalkanes and Haloarenes. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYHaloalkanes and Haloarenesproductsobtainedfollowingreactionsrespectively

More Haloalkanes and Haloarenes Questions

View all

In the given reaction the product P is:

A.[Image Missing]
B.[Image Missing]
C.4
D.[Image Missing]
MediumSolve

Given below is a reaction sequence: $\text{CH}_3\text{CH}_2\text{Cl} \xrightarrow{\text{NaCN}} X \xrightarrow{\text{H}_2/\text{Ni}} Y \xrightarrow{\text{Acetic Anhydride}} Z$ The product '$Z$' in the above reaction is:

A.$\text{CH}_3\text{CH}_2\text{CH}_2\text{NHCOCH}_3$
B.$\text{CH}_3\text{CH}_2\text{CH}_2\text{NH}_2$
C.$\text{CH}_3\text{CH}_2\text{CH}_2\text{CONHCH}_3$
D.$\text{CH}_3\text{CH}_2\text{CH}_2\text{CONHCOCH}_3$
MediumSolve

The $\text{-OH}$ group of an alcohol or the carboxylic acid can be replaced by $\text{-Cl}$ using:

A.Hypochlorous acid
B.Chlorine
C.Hydrochloric acid
D.Phosphorous pentachloride
EasySolve

The correct order of increasing C-X bond reactivity toward nucleophiles among the following is: I. [Missing] II. [Missing] III. $(\text{CH}_3)_3\text{C-X}$ IV. $(\text{CH}_3)_2\text{CH-X}$

A.I < II < IV < III
B.II < III < I < IV
C.IV < III < I < II
D.III < II < I < IV
MediumSolve

Which of the following methods is incorrect for the synthesis of alkenes?

A.Treatment of alkynes with Na in liquid $\text{NH}_3$
B.Heating alkyl halides with alcoholic $\text{KOH}$
C.Treating alkyl halides in aqueous $\text{KOH}$ solution
D.Treating vicinal dihalides with Zn metal
MediumSolve

The correct reaction among the following is:

A.Reaction 1
B.Reaction 2
C.Reaction 3
D.Reaction 4
MediumSolve

The major product formed in the dehydrohalogenation reaction of 2-bromopentane is pent-2-ene. This product formation is based on:

A.Hofmann Rule
B.Huckel's Rule
C.Saytzeff's Rule
D.Hund's Rule
EasySolve

A reaction among the following can generate isonitriles as a major product. (A) $\text{R-X} + \text{HCN} \rightarrow$ (B) $\text{R-X} + \text{AgCN} \rightarrow$ (C) $\text{R-X} + \text{KCN} \rightarrow$ (D) $\text{R-X} + \text{NaCN} \xrightarrow{\text{C}_2\text{H}_5\text{OH}/\text{H}_2\text{O}}$ Choose the most appropriate answer from the options given below:

A.(D) only
B.(C) and (D) only
C.(B) only
D.(A) and (B) only
MediumSolve

This neet chemistry practice question is part of the TopperSquare free question bank. TopperSquare offers 15,000+ chapter-wise NEET MCQs across Physics, Chemistry, and Biology with detailed step-by-step explanations, full mock tests, NEET PYQs (2010–2024), and an AI-powered performance analytics dashboard. browse all neet practice questions → · practice chemistry sets →