Q1: The compound that will undergo SN1 reaction with the fastest rate is
(a)
(b)
(c)
(d) (2024)
Ans: (d)
Reactivity towards ,SN1 depends upon stability of carbocation.
Order of stability is
Q1: The given compound (2023)
is an example of ______.
(a) Benzylic halide
(b) Aryl halide
(c) Allylic halide
(d) Vinylic halide
Ans: C
α-carbon is sp3 carbon which is right next to
This a-position is known as allylic position
Hence,
is allylic halide
Q1: The major product of the following chemical reaction is : (NEET 2021)
(a)
(b)
(c)
(d)
Ans: (d)
Addition of HBr to an alkene in presence of a peroxide (benzoyl peroxide [(C6H5CO)2O2] gives an anti Markownikoff’s product. Anti-Markownikoff’s rule states that hydrogen is added to a more substituted carbon atom of an unsymmetrical alkene.
Q2: The major product formed in dehydrohalogenation reaction of 2-Bromo pentane is Pent-2-ene.This product formation is based on- (NEET 2021)
(a) Hofmann Rule
(b) Huckel's Rule
(c) Saytzeff's Rule
(d) Hund's Rule
Ans: (c)
Major product formed in dehydrohalogenation reaction of 2-bromopentane is pent-2-ene because according to Saytzeff's Rule, in dehydrohalogenation reactions, the preferred product is that alkene which has greater number of alkyl group(s) attached to the doubly bonded carbon atoms.
Q1: Which of the following alkane cannot be made in good yield by Wurtz reaction? (NEET 2020)
(a) n-Heptane
(b) n-Butane
(c) n-Hexane
(d) 2,3-Dimethylbutane
Ans: A
Wurtz reaction is used to prepare symmetrical alkanes like
Using Wurtz reaction, n-Heptane can not be produced in good production because it is unsymmetrical alkane.
Q2: Elimination reaction of 2-Bromo-pentane to form pent-2-ene is: (NEET 2020)
(a) β-Elimination reaction
(b) Follows Zaitsev rule
(c) Dehydrohalogenation reaction
(d) Dehydration reaction
(a) (b), (c), (d)
(b) (a), (b), (d)
(c) (a), (b), (c)
(d) (a), (c), (d)
Ans: (c)
Since β-hydrogen is abstracted it is β-elimination.
Since more substituted alkene is formed (stable and major product), it follows Zaitsev's rule or Saytzev's rule.
Since H and Br are removed, it is dehydrohalogenation.
Q9. The compound C7H8 undergoes the following reactions : (NEET 2018)
The product ‘C’ is
(a) m–bromotoluene
(b) o–bromotoluene
(c) 3–bromo–2,4,6–trichlorotoluene
(d) p–bromotoluene
Ans: (d)
2017
Q10. Identify A and predict the type of reaction (NEET 2017)
(a)
(b)
(c)
(d)
Ans: (d)
m-Bromoanisole gives only the respective meta substituted aniline. This is a substitution reaction which goes by an elimination-addition pathway.
Q1: Consider the reaction, (NEET 2016 Phase 2)
CH3CH2CH2Br + NaCN
This reaction will be the fastest in
(a) ethanol
(b) methanol
(c) N, N' -dimethylformamide (DMF)
(d) Water
Ans: (c)
The reaction,
CH3CH2CH2Br + NaCN
follows SN2 mechanism which is favoured by polar aprotic solvent i.e., N, N'–dimethylformamide (DMF).
Q1: In an SN1 reaction on chiral centers, there is (NEET / AIPMT 2015
(a) inversion more than retention leading to partial racemisation
(b) 100% retention
(c) 100% inversion
(d) 100% racemisation
Ans: (a)
Q1: Which of the following compounds will undergo racemisation when solution of KOH hydrolyses? (AIPMT 2014)
(a) (iii) and (iv)
(b) (i) and (iv)
(c) (iv)
(d) (ii) and (iv)
Ans: (c)
Out of the given four compounds only (iv) compound is chiral and hence only this compound will undergo racemisation.
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1. What are haloalkanes and haloarenes? |
2. What are some common uses of haloalkanes and haloarenes? |
3. How do haloalkanes and haloarenes differ in terms of reactivity? |
4. What are some environmental concerns associated with haloalkanes and haloarenes? |
5. How are haloalkanes and haloarenes named according to IUPAC nomenclature? |
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