Chemistry-
General
Easy
Question
Give the decreasing order of the reaction rates of the following benzyl with HBr
The correct answer is:
The positive charge that develops on benzylic C in this 
reaction is most effectively delocalised by (OMe) group (+R and 
. The 
group withdraws 
density from the ring by 
and 
-Cl) group withdraws s’ from the ring by only. More EDG 
stabilies positive chargeon the benzyl 
atom, whereas EWG (
destabilises the positive charge. Hence, the reactivity order is:I>II>III>IV
Related Questions to study
chemistry-
The product (x) and (y) are:
The product (x) and (y) are:
chemistry-General
physics-
Coherent light is incident on two fine parallel slits 
and 
as shown in fig If a dark fringe occurs at P, which of the following gives possible phase differences for the light waves arriving at P from and ?
Coherent light is incident on two fine parallel slits and as shown in fig If a dark fringe occurs at P, which of the following gives possible phase differences for the light waves arriving at P from and ?
physics-General
chemistry-
There are two paths (I and II) for the preparation of phenyl-2,4-dinitro phenyl ether
Which of the following statements is true?
Path I is feasible, whereas path II is not
Path II is feasible, whereas path I is not
iii. The Cl of (a) undergoes SN reaction because it is activated by the two EWG
groups
iv. The nitration of (c) does not give (b) but it gives because the first nitro group is deactivating, so the second nitro group enters the other ring
There are two paths (I and II) for the preparation of phenyl-2,4-dinitro phenyl ether
Which of the following statements is true?
Path I is feasible, whereas path II is not
Path II is feasible, whereas path I is not
iii. The Cl of (a) undergoes SN reaction because it is activated by the two EWG groups
iv. The nitration of (c) does not give (b) but it gives because the first nitro group is deactivating, so the second nitro group enters the other ring
chemistry-General
physics-
In the set up shown, the two slits 
are not equidistant from the slit S.
The central fringe at O is then
In the set up shown, the two slits are not equidistant from the slit S.
The central fringe at O is then
physics-General
chemistry-
Homolytic bond fission of a covalent single bond gives rise to free radicals. Owing to the presence of an odd electron, free radicals are highly reactive. They have planar to pyramidal geometry depending upon the groups attached to the C-atom having odd electron. Alkyl free radicals are stabilised by hyperconjugation whereas allyl and benzyl free radicals are stabilised by resonance. They are formed as intermediates in the reaction mixture either in the gaseous phase or in non-polar solvents. Addition of HBr to alkenes in presence of peroxide, the substitution of allylic or benzylic hydrogen by ‘Cl’ at high temperature or by ‘Br’ in presence of NBS are examples of reactions involving free radical intermediates.
Arrange the following free radicals in the decreasing order of their stability. 
Homolytic bond fission of a covalent single bond gives rise to free radicals. Owing to the presence of an odd electron, free radicals are highly reactive. They have planar to pyramidal geometry depending upon the groups attached to the C-atom having odd electron. Alkyl free radicals are stabilised by hyperconjugation whereas allyl and benzyl free radicals are stabilised by resonance. They are formed as intermediates in the reaction mixture either in the gaseous phase or in non-polar solvents. Addition of HBr to alkenes in presence of peroxide, the substitution of allylic or benzylic hydrogen by ‘Cl’ at high temperature or by ‘Br’ in presence of NBS are examples of reactions involving free radical intermediates.
Arrange the following free radicals in the decreasing order of their stability.
chemistry-General
chemistry-
Homolytic bond fission of a covalent single bond gives rise to free radicals. Owing to the presence of an odd electron, free radicals are highly reactive. They have planar to pyramidal geometry depending upon the groups attached to the C-atom having odd electron. Alkyl free radicals are stabilised by hyperconjugation whereas allyl and benzyl free radicals are stabilised by resonance. They are formed as intermediates in the reaction mixture either in the gaseous phase or in non-polar solvents. Addition of HBr to alkenes in presence of peroxide, the substitution of allylic or benzylic hydrogen by ‘Cl’ at high temperature or by ‘Br’ in presence of NBS are examples of reactions involving free radical intermediates.
3, 5–dimethylcyclopentene reacts with N–bromosuccinimide (NBS) in CCl4 in presence of light or peroxide. Identify the product.
Homolytic bond fission of a covalent single bond gives rise to free radicals. Owing to the presence of an odd electron, free radicals are highly reactive. They have planar to pyramidal geometry depending upon the groups attached to the C-atom having odd electron. Alkyl free radicals are stabilised by hyperconjugation whereas allyl and benzyl free radicals are stabilised by resonance. They are formed as intermediates in the reaction mixture either in the gaseous phase or in non-polar solvents. Addition of HBr to alkenes in presence of peroxide, the substitution of allylic or benzylic hydrogen by ‘Cl’ at high temperature or by ‘Br’ in presence of NBS are examples of reactions involving free radical intermediates.
3, 5–dimethylcyclopentene reacts with N–bromosuccinimide (NBS) in CCl4 in presence of light or peroxide. Identify the product.
chemistry-General
chemistry-
When isobutene is brominated, the percentage of 
would be approximately
When isobutene is brominated, the percentage of would be approximately
chemistry-General
chemistry-
What is (B) in the following sequence of reactions?
What is (B) in the following sequence of reactions?
chemistry-General
chemistry-
The major product obtained in the acid catalysed dehydration of 
would be 
is
The major product obtained in the acid catalysed dehydration of would be is
chemistry-General
chemistry-
Identify (b) in the following sequence of reactions.
Identify (b) in the following sequence of reactions.
chemistry-General
chemistry-
The appropriate reagent for the following transformation is
The appropriate reagent for the following transformation is
chemistry-General
chemistry-
Major product of the reaction, 
would be
Major product of the reaction, would be
chemistry-General
physics-
A hollow sphere of mass M and radius r is immersed in a tank of water (density 
). The sphere would float if it were set free. The sphere is tied to the bottom of the tank by two wires which makes angle 
with the horizontal as shown in the figure. The tension T1 in the wire is :
A hollow sphere of mass M and radius r is immersed in a tank of water (density ). The sphere would float if it were set free. The sphere is tied to the bottom of the tank by two wires which makes angle with the horizontal as shown in the figure. The tension T1 in the wire is :
physics-General
physics-
An ideal monoatomic gas is carried around the cycle ABCDA as shown in the figure. The efficiency of the gas cycle is :
An ideal monoatomic gas is carried around the cycle ABCDA as shown in the figure. The efficiency of the gas cycle is :
physics-General
physics-
The following graphs shows two isotherms for a fixed mass of an ideal gas. The ratio of r.m.s. speed of the molecules at temperatures T1 and T2 is
The following graphs shows two isotherms for a fixed mass of an ideal gas. The ratio of r.m.s. speed of the molecules at temperatures T1 and T2 is
physics-General
