What’s wrong with the following
IUPAC name?
3
4
2 +

Correct IUPAC name
3
4
2 +

What’s wrong with the following
IUPAC name?
H H CH
3
H H
H C C C C C H
H H OH OH H

H
H
Correct IUPAC name
H CH
3
H H
C C C C C
H H OH OH H
H

What’s wrong with the following
IUPAC name?
CH
3
H
C C
CH
3 CH
2
CH
2
CHCH
2
CHO
CH
3

Correct IUPAC name
CH
3
H
C C
CH
3 CH
2
CH
2
CHCH
2
CHO
CH
3

What’s wrong with the following
IUPAC name?
Br
Br

Correct IUPAC name

What’s wrong with the following structure?
-
Cl O

Cl
Correct structure
O
-

Cl O
Correct structure
H
Cl
+ H
+
O
-

What’s wrong with the following structure?
C N
-

Correct structure
-
C N

Correct structure
H C N
-
C
+ H
+
N

What’s wrong with the following structure?
C O

C
Correct structure
O

What’s wrong with the following structure?
N
O O

O
Correct structure
N
O

What’s wrong with the following structure?
N
O O
-

O
Correct structure
N
O
-

What’s wrong with the following structure?
+
N
O
Nitronium ion
O

O
Correct structure
+
N O
Nitronium ion

What’s wrong with the following structure?
O
O
O

O
Correct structure
O
O

What’s wrong with the following representation?
n = 5 n = 4 n = 3 n = 2 n = 1
E ne rg y le ve l dia gra m

What’s wrong with the following representation?
n = 5 n = 4 n = 3 w ro ng n = 2 n = 1 energy gap between n = & n = 1 should be greater than that between n = infinity & n = 2

Correct representation n = n =
5
4 n = 3 n = 2 n = 1 energy gap between n = & n = 1 should be greater than that between n = infinity & n = 2

What’s wrong with the following representation?
potential energy transition state reaction coordinate

What’s wrong with the following representation?
transition state potential energy intermediate reaction coordinate

What’s wrong with the following representation?
Cl
Cl
Al
Cl
Al
Cl
Cl
Cl

Correct representation
Cl
Cl
Al
Cl
Al
Cl
Cl
Cl

What’s wrong with the following representation?
Cl Cl
C
C
H
H

Correct representation
Cl
Cl
C C
H
H

What’s wrong with the following representation?
H
F
H N
H
B
F
F

Correct representation
H
F
F
N
B
H
H
F

What’s wrong with the following representation?
Cl
Cl
Be
Cl
Be
Cl
Cl
Be
Cl

Correct representation
Cl
Cl
Be
Cl
Be
Cl
Cl
Be
Cl

What’s wrong with the following representation?
O
3
UV
O
2
+
O

Correct representation
O
3
UV
O
2
+ O

Correct representation
O

What’s wrong with the following representation?
2
6
2+
2
-

Correct representation
[Co(H
2
O)
6
] 2+ 2Cl -

What’s wrong with the following representation?
Cell diagram of the standard electrode potential of Cu 2+ (aq)/Cu(s) couple
Pt(s) /H
2
(g) /2H + (aq) Cu
E o = +0.34V
2+ (aq) /Cu(s)

Correct representation
Cell diagram of the standard electrode potential of Cu 2+ (aq)/Cu(s) couple
Pt(s) /H
2
(g, 1atm) /2H + (aq, 1M) Cu 2+ (aq, 1M) /Cu(s)
E o = +0.34V

What’s wrong with the following representation?
Cl CF
2
Cl

Correct representation
Cl CF
2
Cl
“Fish-hook arrow/ half arrow“ to represent flow of an odd electron.

What’s wrong with the following representation?
HO
-
H
CH
3
+ C
C
2
H
5
CH
3
HO
C
H
C
2
H
5

Correct representation
HO
-
H
CH
3
+ C
C
2
H
5
CH
3
HO
C
H
C
2
H
5
Curly arrows flows from
–ve charge center to
+ve charge center.

What’s wrong with the following representation?
CH
3
O
C
O
-
CH
3
C
O
-
O

Correct representation
CH
3
O
C
O
-
CH
3
C
O
-
O
“  ” to represent resonance

What’s wrong with the following representation?
Negative inductive effect of F
CH
3
F

Correct representation
Negative inductive effect of F
CH
3
F
“  ” to represent inductive effect

What’s wrong with the following representation?
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2

Correct representation
1s 2 2s 2 2p 6 3s 2 3p 6 3d 2 4s 2
Electronic configuration should be in ascending order of principal quantum no

What’s wrong with the following representation?
Enthalpy change of combustion of nitrogen = 40 kJ mol -1

Correct representation
Enthalpy change of combustion of nitrogen = + 40 kJ mol -1
+ve/-ve sign should be included in the

H values of endothermic/exothermic enthalpy changes

What’s wrong with the following representation?
Enthalpy Change of formation of water:
H
2
+ O
2

H
2
O

H = -420 kJ mol -1

Correct representation
Enthalpy Change of formation of water:
H
2
(g) +
½
O
2
(g)

H
2
O (l)

H = -420 kJ mol -1
Equations should be balanced.
Physical states should be included in thermochemical equations.

What’s wrong with the following representation?
Partial pressure of H
2
– [H
2
(g)]

Correct representation
Partial pressure of H
2
– P
H
2
(g)
[ ] – concentration expressed in terms of mol dm -3

What’s wrong with the following equation?
RCH
2
OH
KCN
RCH
2
CN

2
Correct reaction pathway
5
2
2

What’s wrong with the following equation?
O
CH
3
C
OH
NaBH
4
CH
3
CH
2
OH

CH
3
Correct reaction pathway
C
O
OH
1
. LiAlH
4
, ether
2
. water
CH
3
CH
2
OH

R
What’s wrong with the following equation?
H
LiAlH
4
C C
RCH
2
CH
3
H
H

R
H
C
Correct reaction pathway
H
H
2
, Pt
RCH
2
CH
3
C
H

What’s wrong with the following equation?
CH
3
H
C C
H conc H
2
SO
4
H
H
CH
3
H
C C
OSO
3
H H
H
H
2
O
H
CH
3
C
OH
H
C
H
H

Correct reaction pathway
CH
3
H
C C
H conc H
2
SO
4
H 0 - 10 o
C
H
CH
3
H
C C
OSO
3
H H
H
H
2
O
H
CH
3
C
OH
H
C
H
H

What’s wrong with the following equation?
R
O
C
OH
+ NH
3
O
R C
NH
2

Correct reaction pathway
R
O
C
OH
+ NH
3
R
O
C
O
-
NH
4
+ heat
O
R C
NH
2

Correct reaction pathway
R
O
C
OH
+ PCl
5
R C
O
Cl
NH
3
O
R C
NH
2
+ HCl

What’s wrong with the following equation?
CH
3
CH
2
C
O
OCH
3 conc. H
2
SO
4
CH
3
CH
2
COOH + CH
3
OH

Correct reaction pathway
CH
3
CH
2
C
O
OCH
3 conc. H
2
SO
4
CH
3
CH
2
COOH + CH
3
OH

What’s wrong with the following equation?
O H
R C + CN
-
R C OH
H
CN

Correct reaction pathway
R
O
C
H
HCN
R
H
C
OH
HO
CN
+
NC
C
H
R

What’s wrong with the following equation?
CH
3
O
C
OH
I
2
, NaOH
HCOO
-
+ CHI
3

Correct reaction pathway
CH
3
O
C
H
I
2
, NaOH
HCOO
-
+ CHI
3

What’s wrong with the following equation?
CH
3
CONH
2
H
3
O
+
CH
3
COOH + NH
3

Correct reaction pathway
CH
3
CONH
2
H
3
O
+
CH
3
COOH + NH
4
+

What’s wrong with the following equation?
2
2
2
4
2

Correct reaction pathway
2
2
he a t
2

What’s wrong with the following equation?
NH
2
NH
2
Br
2
(aq)
Br

Correct reaction pathway
NH
2
NH
2
Br
2
(aq)
Br Br
NH
2
CH
3
COCl
Br
O
NHCCH
3
Br
2
(aq)
O
NHCCH
3
NaOH(aq)
NH
2
Br
Br

What’s wrong with the following equation?
OH
+ CH
3
COOH conc. H
2
SO
4
O
C
O
CH
3

O
-
Correct reaction pathway
O
C
O
CH
3
+ CH
3
COCl

What’s wrong with the following equation?
CH
3
CH
1
.
O
3
CHCH
2
CH
3
2
. H
2
O
CH
3
CHO + CH
3
CH
2
CHO

Correct reaction pathway
CH
3
CH
1
.
O
3
CHCH
2
CH
3
2
. H
2
O, Zn
CH
3
CHO + CH
3
CH
2
CHO

What’s wrong with the following equation?
H
C
O
+
NH
2
NH
2
H
C
NNH
2

H
C
O
Correct products
H
C
NNH
2
+
NH
2
NH
2
H
C N
N C
H

What’s wrong with the following equation?
OH
N N
+
N N
OH
+

N
+
N +
Correct product
OH
N
N
OH

2
What’s wrong with the following equation?
OH
+ Na
2
CO
3
2
ONa
+ H
2
O + CO
2

OH
Correct products
ONa
+ Na
2
CO
3
+ NaHCO
3
Phenol is less acidic than H
2
CO
3
, but more acidic than HCO
3
.

What’s wrong with the following equation?
Two dipeptides can be formed from 2-aminoethanoic acid and
2-aminopropanoic acid
NH
2
NH
2
C
H
H
H
C
H
COOH + NH
2
O
C N
H
H
C
CH
3
H
C
CH
3
COOH NH
2
COOH
H
C
CH
3
COOH
NH
2
+ NH
2
H
O
C
CH
3
C N
H
H
C
H
H
C
H
COOH
COOH

H
H
NH
2
C
O
Correct products
C
H
N
*
C
H
CH
3
CH
3
H
*
C
H
N
C
H
C
HOOC
COOH
O
H
NH
2
C
H
COOH
H
N
H
O
C
*
C
H
CH
3
NH
2
CH
3
H
*
C
NH
2
O
H
C
N
C
H
COOH
H

What’s wrong with the following equation?
CH
3
CH
2
H
C
OH
CH
2
CH
2
CH
3 conc. H
2
SO
4 heat
CH
3
CH
2
C
H
C
CH
2
CH
3
H

CH
3
CH
2
H
C
OH
CH
2
Correct products
CH
3
CH
2
CH
2
CH
3 conc. H
2
SO
4 heat
H
CH
3
CH
2
C
C
H
CH
3
C
H
C
C
C
CH
2
CH
3
H
H
CH
2
CH
3
CH
2
CH
2
CH
3
H
H
CH
3
C
H
C
CH
2
CH
2
CH
3

What’s wrong with the following equation?
CH
3
CH
2
CH
3
C CH
2
CH
2
Br
CH
3 alcoholic KOH heat
CH
3
CH
2
C
H
C
CH
2
CH
3
H

Correct products
H
C
CH
2
CH
3
C
CH
2
CH
2
CH
3
H
CH
3
CH
2
CH
3
C CH
2
Br
CH
2
CH
3 a lc oholic KOH he a t
CH
3
CH
2
H
CH
3
CH
2
C
C
H
CH
3
C
H
C
C
C
CH
H
H
H
H
2
CH
CH
2
3
CH
3
CH
2
CH
2
CH
3
CH
3
C
H
C
CH
2
CH
2
CH
3

B
-
Correct products
H
C
C H
C
X
C
H
H
C
C H
C
X
C
H
B
-
H
C
C H
C
X
C
H
B
-

What’s wrong with the following equation?
4
2
2
2

Correct product
2 Na(s) + O
2
(g) main reaction
4 Na (s) + O
2
(g) side reaction
Na
2
O
2
(s)
2 Na
2
O (s)

What’s wrong with the following reaction conditions?
3

Correct reaction conditions using AgNO
3
(aq) + HNO
3
(aq) to detect chloride ion

What’s wrong with the following reaction conditions?

Correct reaction conditions using burning splint in the test of hydrogen

What’s wrong with the following reaction conditions?
using BaCl
2
(aq) to detect sulphate ion

Correct reaction conditions using BaCl
2
(aq) + HCl(aq) to detect sulphate ion

What’s wrong with the following reaction conditions?
using LiAlH
4
, water in the reduction of carbonyl compounds

Correct reaction conditions using LiAlH
4
, ether in the reduction of carbonyl compounds
LiAlH
4
+ 4H
2
O

Li + + Al 3+ + 4OH + 4H
2

What’s wrong with the following reaction conditions?
using NaNO
3
(s) + HCl(aq) in the azotization of aromatic amines

Correct reaction conditions using NaNO
2
(s) + HCl(aq) (<5 o C) in the azotization of aromatic amines

What’s wrong with the following description?
o
o
o
o

Correct description
o
o
o
o

What’s wrong with the following description?
Landfilling is an appropriate disposal method for PVC.

Correct description
Landfilling is not regarded as an appropriate disposal method for PVC because PVC is non-biodegradable;
The proper way is by incineration (with adequate supply of air at sufficient higher temperature) and treat the flue gas in wet scrubber with Na
2
CO
3
(aq).

What’s wrong with the following description?
first emission line in the Balmer series involves electronic transition between n = 2 to n = 0.

Correct description quantum number can have values 1,2,3 etc ; first emission line in Balmer series involves electronic transition between n = 3 to 2 ; convergence limit in Balmer series involves electronic transition between n = infinity to
2.

What’s wrong with the following expression?
CH
3
COOH(aq) + H
2
O(l)
CH
3
COO
Kc =
[CH
3
COO
-
(aq)] [H
3
O
+
(aq)]
[CH
3
COOH(aq)]
-
(aq)
+ H
3
O
+
(aq)

Correct expression
CH
3
COOH(aq) + H
2
O(l) CH
3
COO
OR
Kc =
[CH
3
COOH(aq)] [H
2
O(l)]
[CH
3
COO
-
(aq)] [H
3
O
+
(aq)]
Ka =
[CH
3
COO
-
(aq)] [H
3
O
+
(aq)]
[CH
3
COOH(aq)]
-
(aq)
+
H
3
O
+
(aq)

What’s wrong with the following expression?
CH
3
COOH + C
2
H
5
OH(l)
Kc =
CH
3
COOC
2
H
5
(l) + H
2
O(l)
[CH
3
COOC
2
H
5
(l)]
[CH
3
COOH(l)][C
2
H
5
OH(l)]

Correct expression
CH
3
COOH + C
2
H
5
OH(l) CH
3
COOC
2
H
5
(l) + H
2
O(l)
Kc =
[CH
3
COOC
2
H
5
(l)] [H
2
O(l)]
[CH
3
COOH(l)][C
2
H
5
OH(l)]

What’s wrong with the following expression?
+
+
-
+
-

Correct expression
AgCl(s) Ag
+
(aq) + Cl
-
(aq)
[Ag
+
(aq)][Cl
-
(aq)]
Kc' =
[AgCl(s)] is a constant term.

What’s wrong with the following expression?
The decay of carbon-14 starts after the death of living things.

Correct expression
The ratio of carbon-12 and carbon-14 remains unchanged in a living organism, but decreases slowly after the death of living things.

What’s wrong with the following expression?
In paper chromatography, cellulose in the filter paper is the stationery phase.

Correct expression
In paper chromatography, the thin film of water on the chromatography paper acts as the stationary phase and that partition is the underlying principle of paper chromatography.

What’s wrong with the following expression?
criteria in choosing an indicator – pH range of colour change close to the equivalence point

Correct expression criteria in choosing an indicator – the pH range of colour change of the indicator falls into the steepest part of the titration curve / pK i is very close to the pH of the solution at equivalence point.

What’s wrong with the following expression?
A rise in temp increases the forward reaction rate and the equilibrium position shifts to the product side.

Correct expression
A rise in temp. increases both the forward
& backward reaction rates.
For endothermic reaction the extent of increase in forward reaction rate is greater than that of backward reaction rate.
Thus the position of equilibrium shifts to the product side. In case of endothermic/exothermic reaction, Kc increases/decreases with temp .

What’s wrong with the following expression?
catalyst lowers the activation energy of the reaction.
catalyst increases both reaction rate & yield.

Correct expression catalyst provides a new pathway with lower activation energy.
catalyst increases the reaction rate but yield remains unchanged .

What’s wrong with the following expression?
b.p. of H
2
O > OF
2 because intermolecular hydrogen bond exists in water.

Correct expression b.p. of H
2
O > OF
2 because intermolecular hydrogen bond exists in water and van der
Waals’ force between OF
2
.
more energy is needed to overcome hydrogen bond, accounting for the higher boiling point.

What’s wrong with the following expression?
Boiling point of H
2
O > H
2
S because O is more electronegative and forms stronger hydrogen bonding.

Correct expression
Boiling point of H
2
O > H
2
S because O is more electronegative intermolecular hydrogen bond in H
2
O
Van der Waals’ forces in H
2
S is weaker more energy is needed to overcome hydrogen bond, accounting for the higher boiling point.

What’s wrong with the following expression?
hcp, fcc and bcc are close-packing arrangement.

Correct expression
Hexagonal close-packing and face-centred cubic close-packing have the maximum coordination number, which is equal to 12.
Body-centred cubic has open structure and the coordination number is equal to 8.

What’s wrong with the following expression?
NaCl has ‘face-centred cubic structure’ and
CsCl has ‘body-centred cubic structure’

Correct expression
In NaCl, both Na + and Cl ions adopt facecentred cubic lattices, which interpenetrate each other.
The structure shows 6:6 coordination.
In CsCl, both Cs + and Cl ions adopt simple cubic lattices, which interpenetrate each other .
The structure shows 8:8 coordination .

What’s wrong with the following expression?
oxidative rancidity of oils and fats involve
RCOO.

Correct expression oxidative rancidity of oils and fats involve alkylperoxyl radical (ROO.) but not the carboxyl radical (RCOO.);

What’s wrong with the following expression?
The functional group in benzoic acid is
‘alkanoic acid’ and ‘alkanol’ is the functional group of phenol.

Correct expression
‘Carboxylic acid’ is the functional group of benzoic acid.
‘Hydroxyl group’ is the functional group of phenol.

What’s wrong with the following expression?
“Chromium is harmful”

Correct expression
Chromium compounds are toxic to aquatic life.

What’s wrong with the following expression?
Aspirin has sude effects.

Correct expression
Aspirin could cause damage to stomach lining.

What’s wrong with the following expression?
Order is the sum of the powers of the concentration terms in the rate equation.

Correct expression
Order is the sum of the powers of the concentration terms in the experimentally determined rate equation.

What’s wrong with the following expression?
Half-life of a first order reaction increases with initial concentration.

Correct expression
Half-life of a first order reaction is independent of initial concentration or pressure.

What’s wrong with the following expression?
With an alkali, halogen forms halide and halate(V).

Correct expression
With an alkali, chlorine forms ClO and ClO
3
under different conditions , bromine forms mainly BrO
3
-
IO
3
.
with some BrO , and iodine only

What’s wrong with the following expression?
Boric acid is a tribasic acid.

Correct expression
Boric acid is a monobasic acid.

What’s wrong with the following expression?
CCl
4 is stable towards water, but SiCl hydrolyses readily in water. This is because C
4 is more electronegative than Si.

Correct expression
Low-lying vacant orbital is not available in carbon.

What’s wrong with the following expression?
Phenol is more acidic than ethanol because the negative charge on the phenoxide ion can delocalise into the benzene ring.

Correct expression
Due to the delocalization of the negative charge, the phenoxide ion is stablized. The following equilibrium shifts to the RHS .
OH O
-
+
H
+

What’s wrong with the following expression?
Tertiary carbocation is more stable than the primary carbocation.

Correct expression
Tertiary carbocation is more stable than the primary carbocation.
Positive inductive effect of the methyl group stabilises the tertiary carbocation.