ISOMERISM Flashcards
1
Q
CHAIN ISOMERISM
A
SAME MOLECULAR FORMULA BUT THERE IS A CHANGE IN STRUCTURE OF PARENT CHAIN OR SIDE CHAIN
LIKE PENTANE, ISOPENTANE AND NEOPENTANE
2
Q
POSITION ISOMERISM
A
SAME MOLECULAR FORMULA BUT DIFFER IN POSITION OF FUNCTIONAL GROUP or substituent or unsaturation
3
Q
FUNCTIONAL GROUP ISOMERISM
A
SAME MOLECULAR FORMULA BUT it is arises by change in functional group
4
Q
METAMERISM
A
it is arises by change in structure of alkyl group attached to bivalent functional group
5
Q
ring chain isomer
A
has same molecular formula but if it is possible to draw open chain and ring structures then those isomers are called ring chain isomers
6
Q
number of isomers of c6h14
A
5
7
Q
what is VICINAL dichloride
A
FUNCTIONAL GROUPS ARE CONNECTED TO ADJACENT CARBON ATOMS
SEE STRUCTURE
8
Q
what is GEMENAL dichloride
A
MORE THAN 1 FUNCTIONAL GROUP IS CONNECTED TO ONE CARBON ATOM
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9
Q
example of ring chain isomer and draw all its possible ring chain and straight chain isomers
A
c4h8
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10
Q
functional group isomer of alcohol
A
ethers
11
Q
functional group isomer of aldehyde
A
ketones
12
Q
functional group isomer of Carboxyllic acids
A
ester
13
Q
functional group isomer of cyanide
A
isocyanides
14
Q
functional group isomer of nitroalkane
A
alkyl nitrite
15
Q
functional group isomer of 1 degree amine
A
2 and 3 degree amines
16
Q
functional group isomer of alkyne
A
alkadienes
17
Q
functional group isomer of THIOALCOHOL
A
thioethers
18
Q
write all isomers of c7h8o(aromatic containing benzene ring)
A
5 STRUCTURES
19
Q
minimum number of carbon atoms required to have chain isomer
A
4
20
Q
write all isomers of c3h6o
A
SEE STRUCTURES
21
Q
write all isomers of c3h6o2
A
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22
Q
number of acids and esters possible for c4h8o2
A
2 and 4
23
Q
isomer of nitromethane
A
methyl nitrite
24
Q
functional group isomers of c3h9n
A
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25
functional group isomers of c3h9n
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26
functional group isomers of c4h6
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27
what are conjugated pi bonds
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28
what are cumulative pi bonds
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29
what are dispersed pi bonds
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30
acetaldehyde and acetone are
no isomers
31
glucose and fructose are
functional group isomers
32
what is a bivalent functional group
a functional group with a valency of 2
33
what are metamers
it is arised by change in structure of alkyl group attached to bivalent functional groups
34
what is the metamer of 2-pentanone
3-pentanone
35
how many structural isomers are possible for c3h8o
3
36
how many structural isomers are possible for c4h10o
7
37
how many structural isomers are possible for c3h9n
4
38
how many structural isomers are possible for c4h11n
8
39
number of primary secondary and tertiary amines in the isomers of c3h9n
2
1
1
40
number of primary secondary and tertiary amines in the isomers of c4h11n
4
3
1
41
what is tautomerism and tautomers
the compounds having same molecular formula and there is a interconnection between the compounds by change in the position of atom(mostly hydrogen) those compounds are called tautomers and that phenomenon is called tautomerism
42
tautomers are in what kinda equilibrium
dynamic
43
tautomers are also which isomers?
functional group isomers
44
what is the dyad system
if h shift takes place 2 adjacent atoms
45
what is triad system
if h shift takes place from 1st atom to 3rd atom
46
what is keto and enol form
keto is aldehyde or ketone
| eno is alcohol
47
what is keto-enol tautermerism
keto form changes to enol form and vice versa
48
example of triad system
actaldehyde to vinyl alcohol
| SEE STRUCTURES
49
example of dyad system
h-cn
| cn-h
50
example of keto-enol tautermerism and write what is the keto and enol form
actaldehyde(triad system) to vinyl alcohol(enol form)
51
when is keto enol tautomerism observed
it is observed when alpha h is more acidic in the compounds
52
example of compounds which show keto-enol tautomerism
aldehyde, ketone, no2, cn, no compounds
53
c3h6br2 can have how many geminal and vicinyl dibromide
2 gem
| 1 vic
54
when are two compounds said to be isomers
when their nomenclature is different
55
what is carbonyl group
c double bond o
56
what are the ways to identify the compounds in which tautomerism will take place
carbonyl group should have an alpha hydrogen attached to sp3 carbon atom
if the carbon connected to the carbonyl does not have a hydrogen attached to it then no tautomerism is possible
57
tautomerism takes place in which mediums
acidic and basic
58
explain tautomerism in basic medium and write structures
In basic conditions, a ketone or an aldehyde acts as a Brønsted acid donating a proton from an α-carbon to a base in the solution. This process gives a resonancely stabilized enolate anion
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59
explain tautomerism in acidic medium and write structures
here a keto form changes into an enol form
an alpha hydrogen shifts to the o in cho and finally forms oh
the initial compound is ch3coh which is called keto form
the final compound is ch2 double bond coh(h) this is called enol form
SEE STRUCTURES FOR CLARITY
60
what is active methylene group
the ch2 group present between 2 co groups
61
example of active methylene groups
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62
what is enolization
conversion of keto form to enol form
63
what are the 5 points enolization depends on
```
acidic nature of alpha hydrogen
intra molecular h bond
aromatic nature/conjugation
steric factor
effect of solvent
```
64
in simple aldehydes and ketones
keto form is much more stable than enol form
65
what is pka value
indicates acidic nature of the alpha hydrogen
66
give examples where pka of 1 compound is greater than another
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67
give examples where percentage of enol form of 1 compound is greater than another
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68
what is special about the active methylene group
the active methylene group hydrogens is more acidic than a normal alpha hydrogen
69
give examples of tautomerism in various compounds
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70
what can you say about the acidic nature of alpha hydrogen in ester and the acidic hydrogen in ketones and aldehydes
the acidic nature of alpha hydrogen in ester is less than the acidic nature of alpha hydrogen in ketones and aldehydes
71
give an example where aromatic is more stable
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72
explain steric effect
as the size of R increases the percentage of enol decreases due to steric factor.
it effects the planarity of the molecule
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73
give examples of steric effect
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74
what happens when the polarity of the solvent increases
the percentage of enol form decreases and the percentage of keto form increases because keto form is more salvated with solvent
75
give an example of a structure depicting effect of solvent
SEE STRUCTURES`
76
what is the order of percentage of enol and keto form of acetyl acetone in air toluen and h20
enol
air(or) n hexane>toluene>h20
keto
nhexane
77
what is gamma tautomerism
the phenomenon by which a hydrogen from a gamma carbon gets transferred
78
give 2 examples of gamma tautomerism
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79
what structures are wrong
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80
give examples of structures which can show tautomerism
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81
which hydrogen is more acidic
the one connected to more electronegative atom.....
82
give examples to show how shifting of pi bonds take place
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83
tautomerism is obtained by the simultaneous
shifting of h atom
| shift of double bond at 1 and 3 positions
84
how is the enolic form stabilised
intramolecular hydrogen bonding
85
what happens in 1,3 dicarbonyl compounds and why
the enolic form is much greater than in acetaldehyde and acetone because of intramolecular h bonding
86
why is the enolic form in acetyl acetone much higher than in acetoacetic ester
because ketone is a much better withdrawing group than ester group
87
which kinda bond makes enol content much more stable
conjugated pi bond
88
why is the enol content more in hexane than in h2o
since h20 forms h bonds with keto forms thereby inhibiting the intermolecular h bonding of the enol form
89
enol order in different solvents?
hexane>benzene>acetone>methanol>h2o
90
what is the increasing order of enol content
aldehyde < ketone < ketoester < ketoester with ph group < dial < ketoaldehyde < diketone
91
what are geometrical isomers
isomers which have the same structural formula but differ in the relative spatial arrangement of atoms or groups around the double bonds are called geometrical isomers
92
what is a cis isomer
isomers in which similar groups of atoms or groups lie on the same side of the double bond
93
what is a trans isomer
isomers in which similar groups of atoms or groups lie on the opposite side of the double bond
94
when is geometrical isomerism possible
only when each of the doubly bonded carbon atom has two different groups
95
in which cases are geometric isomers not possible
when similar atoms or groups are on one or both the carbons of the double bond
96
what is the difference in melting point in cis and trans isomers
the melting point of trans is greater than cis
97
what is the difference in boiling point in cis and trans isomers
the boiling point of cis is greater than trans
98
what is the dipole moment of cis and trans
cis has a definite dipole moment while trans has no dipole moment
99
draw structures of cis and trans
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100
draw the 3 types of geometric isomers
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101
higher priority is assigned to atoms
the atom which is connecting c double bond c and which has higher atomic number
102
if isotopes of the same element are attached
the isotope with the higher mass number will ahve the higher priority
103
what is zusammen or z configuration
if atoms or groups of higher priority are on the same side of the double bond
104
what is entgegan or e configuration
if atoms or groups of higher priority are on the opposite side of the double bond
105
what is cis and trans in terms of z and e
cis is z
| trans is e
106
what is syn configuration
in aldoximes when h and oh groups are on the same side the isomer is known as syn
107
what is anti configuration
in aldoximes when h and oh groups are on the opposite side the isomer is known as anti
108
give examples to show how cis and trans isomers are possible across a single bond
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109
give examples to show how geometrical isomerism is possible in cyclic compounds
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110
formula of number of geometric isomers when terminal groups are different
2^n
111
formula of number of geometric isomers when terminal groups are same and n is even
2^n-1+2^(n-2)/2
112
formula of number of geometric isomers when terminal groups are different and n is odd
2^n-1+2^(n-1)/2
113
what atoms are geometric isomers
cn nn cc
114
if two identical groups are present on sp2 carbon of double bond then?
it can't exhibit geometric isomerism
115
name the possible names of ketoxime wrt R and R'
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116
upto 7 member ring
there is no gi due to ring strain
117
which is generally more stable cis or trans
trans
118
in a 8-11 member carbon ring what is the order of stability
cis is more stable than trans
119
in a greater than 11 member ring what is the order of stability
trans is more stable than cis
120
draw the cis and trans structures of cyclooctene
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121
if the groups connected to c double bond c are identical then the order of priority
depends on the "highest atomic number" of the atoms connected to the first carbon connected to the double bond
122
how to transform double and triple bonds while choosing the priority
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remember the the main thing you should remember here is that the double and triple bonds are converted into single bonds and the remaining valency of the atoms are filled with only the atoms connected by the double bond
123
what if there are odd number of cumulative pi bonds
there is geometric isomerism
124
what if there are even number of cumulative pi bonds
no geometric isomerism
