NIELIT University(Govt. of India Institution) B.Tech/ M.Tech
Last Date to Apply : 15th September | Campuses in Agartala, Aizawl, Ajmer, Aurangabad, Calicut, Imphal, Itanagar, Kohima, Gorakhpur, Patna & Srinagar
Strong and Weak bases, Nucleophilic Substitution are considered the most difficult concepts.
SN2 Reaction, SN1 Reaction are considered the most asked concepts.
86 Questions around this concept.
The major product obtained in the following reaction is :
In a face-centered cubic lattice atoms A are at the corner points and atoms B at the face-centered points. If atom B is missing from one of the face-centered points, the formula of the ionic compound is :
Tertiary alkyl halides are practically inert to substitution by mechanism because of
JEE Main 2025: Sample Papers | Syllabus | Mock Tests | PYQs | Video Lectures
JEE Main 2025 Formula: Physics | Maths | Chemistry
JEE Main 2025: Preparation Guide | High Scoring Topics | Study Plan 100 Days
The organic chloro compound, which shows complete stereochemical inversion during a reaction, is
Which branched chain isomer of the hydrocarbon with molecular mass 72u gives only one isomer of mono-substituted alkyl halide?
Decreasing order towards SN 1 reaction for the following compounds is:
Which among the following halide/s will not show $\mathrm{S}_{\mathrm{N}} 1$ reaction
(A)$\mathrm{H}_2 \mathrm{C}=\mathrm{CH}-\mathrm{CH}_2 \mathrm{Cl}$
(B) $\mathrm{CH}_3-\mathrm{CH}=\mathrm{CH}-\mathrm{Cl}$
Choose the most appropriate answer from the options given below :
Last Date to Apply : 15th September | Campuses in Agartala, Aizawl, Ajmer, Aurangabad, Calicut, Imphal, Itanagar, Kohima, Gorakhpur, Patna & Srinagar
170+ Recruiters Including Samsung, Zomato, LG, Adobe and many more | Highest CTC 47 LPA
Given below are two statements:
Statement - I : High concentration of strong nucleophilic reagent with secondary alkyl halides which do not have bulky substituents will follow $\mathrm{S}_{\mathrm{N}}{ }^2$ mechanism.
Statement - II : A secondary alkyl halide when treated with a large excess of ethanol follows $\mathrm{S}_{\mathrm{N}}{ }^1$ mechanism.
In the light of the above statements, choose the most appropriate from the options given below:
Which one of the following bases is not present in DNA?
Rate of the reaction
is fastest when is
Most common bases that we have use are alc.KOH and aqueous NaOH. In alc.KOH, we have EtO-(CH3-CH2-O-) as the base while in aqueous NaOH, the base is OH-. The strength of these two bases are given below:
CH3-CH2-O- > OH-
Because CH3-CH2- is the releasing group and hence it unstabilize the O-, thus it reacts faster and hence it is stronger base. The reactions occurs as follows:
For alc.KOH:
For aq.NaOH:
The general reaction occurs as follows:
Mechanism
The general reaction occurs as follows:
Elimination-Addition Mechanism(I)
Very stong base such as sodium or potassium amide react with aryl halide, even those without electron withdrawing substituents to give products corresponding to nucleophilic substitution of halide by the base.
Mechanism
Aryl halides are extremely less reactive towards nucleophilic substitution reactions due to the following reasons:
Chlorobenzene can be converted into phenol by heating in aqueous sodium hydroxide solution at a temperature of 623K and a pressure of 300 atmospheres.
The presence of an electron withdrawing group (-NO2 ) at ortho- and para-positions increases the reactivity of haloarenes.
"Stay in the loop. Receive exam news, study resources, and expert advice!"