Which ofthe following complexes exists as pair of enantiomers ?
trans-[Co(en)2Cl2]+
[Co(NH3)2Cl2]+
[Co{P(C2H5)3}2ClBr]
[Cr(en)3]3+
What is the correct order of basicity among the following compounds ?
II > I > III > IV
I > II > III > IV
III > I > II > IV
I > III > II > IV
D.
I > III > II > IV
The correct order of basicity is I > III > II > IV.
The conjugate acid formed by addition of a proton to I is stabilised by two equivalent resonance structures and hence, compound I is the most basic. Further 2° amines (III) are more basic than 1 ° amines (II) while amides (IV) are least basic due to delocalisation of lone pair of electrons of N over the CO group.
Arrange the following nucleophiles in the decreasing order of nucleophilicity :
(A) CH3COO-
(B) CH3O-
(C) CN-
(D)
C, B, A, D
A, B, C, D
C, C, B, A
B, C, A, D
Assertion : Thiophene present in commercial benzene as an impurity can be removed by shaking the mixture with cold concentrated H2SO4.
Reason : Thiophene is a heterocyclic aromatic compound.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Ease of nucleophilic addition in the given compounds is
I > III > II
II > III > I
II > I > III
III > I > II
Which of the following species is not aromatic?
Benzene
Cyclooctatetraenyl dianion
Tropylium ion
Cyclopentadienyl cation
Select the correct statement.
Geometrical isomer may differ in dipole moment and visible/UV spectra.
Complexes of the type [Ma3b3] can also have facial (fac) and meridional (mer) isomer.
No optical isomer exists for the complex trans- [Co(en)2Cl2]+.
All of these.