Multiple Choice QuestionsAssertion : Hydroxyketones are not directly used in Grignard reaction.
Reason : Grignard reagents react with hydroxyl group.
If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
A.
If both assertion and reason are true and the reason is the correct explanation of the assertion.
Hydroxyketones are not directly used in Grignard reaction as these are very reactive and will react with hydroxyl group.
Which of the following possess highest melting point?
p-dichlorobenzene
m-dichlorobenzene
o-dichlorobenzene
chlorobenzene
A.
p-dichlorobenzene
p-dichlorobenzene molecule has symmetrical structure. It can fit well in its crystal lattice. The intermolecular forces of attraction are strong. Hence, it possesses highest melting point among given options.
Chloroform , when kept open , is oxidised to :
CO2
COCl2
CO2 , Cl2
none of these
B.
COCl2
Chloroform is oxidised to a poisonous gas , phosgene (COCl2) by atmospheric gas .
CHCl3 + O COCl2 + HCl
Assertion : Trans-2-butene on reaction with Br2 gives meso-2,3-dibromobutane.
Reason : The reaction involves syn -addition of bromine.
If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
C.
If assertion is true but reason is false.
With trans-2-butene, the product of Br2 addition is optically inactive due to the formation of symmetric mesa compounds.
Assertion : Benzyl bromide when kept in acetone water it produces benzyl alcohol.
Reason : The reaction follows SN2 mechanism.
If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
A.
If both assertion and reason are true and the reason is the correct explanation of the assertion.
When benzyl bromide is kept in acetone, it produces benzyl alcohol.
An asymmetric carbon atom is which
attached three atoms or groups are different
attached all the atoms or groups are different
attached two atoms or groups are different
attached all the atoms or groups are the same
B.
attached all the atoms or groups are different
An asymmetric carbon atom is defined as a carbon within an organic compound that contains four different atoms or groups of atoms (substituents) bonded to it.
CH3-CH2-Cl A, the product is :
CH3CH2OK
CH3CHO
CH3CH2OCH2CH3
CH2=CH2
D.
CH2=CH2
Alkyl halides undergoes - elimination in presence of alcoholic KOH, to give unsaturated hydrocarbons. This is also called dehydrodehalogenation of alkyl halides.
CH3.CH2Cl + KCl + H2O
Which of the following compounds reacts slower than benzene in electrophilic brornination?
A.
Nitro group (-NO2) deactivates the benzene ring in nitrobenzene due to -M effect.
The reaction :
C2H5OH SOCl2 C2H5Cl + SO2 + HCl is known as :
Kharasch effect
Williamson's synthesis
Darzen's procedure
Hunsdiecker reaction
C.
Darzen's procedure
Darzen's method : Alkyl halides are prepared when thionyl chloride and alcohols are refulxed in presence of pyridine.
R-OH + SOCl2 R-Cl + SO2 + HCl
By products of this reaction are gases (SO2 , HCl) so can be easily removed from the reaction mixture.
Which ofthe following is involved in Sandmeyer's reaction ?
Ferrous salt
Diazonium salt
Ammonium salt
Cupromonium salt
B.
Diazonium salt
Aryl halides can be prepared by the decomposition of aryl diazonium salts in presence of copper halides solution dissolved in the corresponding halogen acid, the diazo group is replaced by a halogen atom. This reaction is known as Sandmeyer reaction.
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