>
Chemistry
List of top Chemistry Questions
A
l
2
O
3
Al _{2} O _{3}
A
l
2
O
3
is reduced by electrolysis at low potentials and high currents. If
4.0
×
1
0
4
4.0 \times 10^{4}
4.0
×
1
0
4
amperes of current is passed through molten
A
l
2
O
3
Al _{2} O _{3}
A
l
2
O
3
for 6 hours, what mass of aluminium is produced ? (Assume
100
%
100 \%
100%
current efficiency, at. mass of
A
l
=
27
g
m
o
l
−
1
Al =27\, g\, mol ^{-1}
A
l
=
27
g
m
o
l
−
1
) -
NEET (UG) - 2009
NEET (UG)
Chemistry
Electrochemistry
An organic compound on heating with
C
u
O
CuO
C
u
O
produces
C
O
2
CO_2
C
O
2
, but no water. The organic compound may be
KCET - 2009
KCET
Chemistry
Haloalkanes and Haloarenes
Which of the following does not show optical isomerism? (en = ethylenediamine)
NEET (UG) - 2009
NEET (UG)
Chemistry
coordination compounds
Decreasing order of stability of ions is (i)
\quad
C
H
3
−
C
+
H
−
C
H
3
CH_3 - C^+H - CH_3
C
H
3
−
C
+
H
−
C
H
3
(ii)
\quad
C
H
3
−
C
+
H
−
O
C
H
3
CH_3-C^+H-OCH_3
C
H
3
−
C
+
H
−
OC
H
3
(iii)
\quad
C
H
3
−
C
+
H
−
C
O
C
H
3
CH_3 - C^+H - COCH_3
C
H
3
−
C
+
H
−
COC
H
3
AIIMS - 2009
AIIMS
Chemistry
Organic Chemistry- Some Basic Principles and Techniques
In the balanced chemical reaction
I
O
3
−
+
a
I
−
+
b
H
+
→
c
H
2
O
+
d
I
2
IO^{-}_{3}+aI^{-}+bH^{+}\to cH_{2}O+ dI_{2}
I
O
3
−
+
a
I
−
+
b
H
+
→
c
H
2
O
+
d
I
2
a
,
b
,
c
a, b, c
a
,
b
,
c
and
d
d
d
respectively corresponds to
AFMC - 2009
AFMC
Chemistry
Redox reactions
Ribose sugar is present in
KCET - 2009
KCET
Chemistry
Biomolecules
IUPAC name of
(
C
H
3
)
3
C
C
l
(CH_3)_3CCl
(
C
H
3
)
3
CCl
KCET - 2009
KCET
Chemistry
Organic Chemistry- Some Basic Principles and Techniques
The rate equation for a reaction :
A
→
B
A \rightarrow B
A
→
B
is
r
=
K
[
A
]
∘
r = K[A]^\circ
r
=
K
[
A
]
∘
. If the initial concentration of the reactant is a mol
d
m
−
3
dm^{-3}
d
m
−
3
, the half life period of the reaction is
KCET - 2009
KCET
Chemistry
Chemical Kinetics
Excess of carbon dioxide is passed through
50
m
L
50 \,mL
50
m
L
of
0.5
M
0.5\, M
0.5
M
calcium hydroxide solution. After the completion of the reaction, the solution was evaporated to dryness. The solid calcium carbonate was completely neutralised with
0.1
N
0.1\, N
0.1
N
Hydrochloric acid. The volume of Hydrochloric acid required is (At. mass of calcium =
40
40
40
)
KCET - 2009
KCET
Chemistry
Some basic concepts of chemistry
What are
X
X
X
and
Y
Y
Y
in the following reaction sequence $C _{2} H _{5} OH \ce{->[{ Cl _{2} }]} \underline{X} \ce{->[{ Cl _{2}}]}\underline{Y}$
VITEEE - 2009
VITEEE
Chemistry
Alcohols, Phenols and Ethers
The type of bonds present in sulphuric anhydride are
VITEEE - 2009
VITEEE
Chemistry
Chemical bonding and molecular structure
The chemical entities present in thermosphere of the atmosphere are
VITEEE - 2009
VITEEE
Chemistry
Atmospheric pollution
p
H
pH
p
H
of a buffer solution decreases by
0.02
0.02
0.02
units when
0.12
g
0.12\,g
0.12
g
of acetic acid is added to
250
m
L
250\, mL
250
m
L
of a buffer solution of acetic acid and potassium acetate at
2
7
∘
C
27^{\circ} C
2
7
∘
C
. The buffer capacity of the solution is
VITEEE - 2009
VITEEE
Chemistry
Buffer Solutions
What is the
[
O
H
−
]
[OH^-]
[
O
H
−
]
in the final solution prepared by mixing
20.0
m
L
20.0\, mL
20.0
m
L
of
0.050
M
H
C
l
0.050\, M\, HCl
0.050
M
H
Cl
with
30.0
m
L
30.0\, mL
30.0
m
L
of
0.10
M
B
a
(
O
H
)
2
0.10\, M Ba(OH)_2
0.10
MB
a
(
O
H
)
2
?
NEET (UG) - 2009
NEET (UG)
Chemistry
Equilibrium
The equivalent conductance of
M
32
\frac{ M }{32}
32
M
solution of a weak monobasic acid is
8.0
m
h
o
c
m
2
8.0\, mho\, cm ^{2}
8.0
mh
o
c
m
2
and at infinite dilution is
400
m
h
o
c
m
2
400\, mho\, cm ^{2}
400
mh
o
c
m
2
, The dissociation constant of this acid is -
NEET (UG) - 2009
NEET (UG)
Chemistry
Equilibrium
The oxidation state of
F
e
Fe
F
e
in the brown ring complex :
[
F
e
(
H
2
O
)
5
N
O
]
S
O
4
[Fe(H_2O)_5 NO]SO_4
[
F
e
(
H
2
O
)
5
NO
]
S
O
4
is
KCET - 2009
KCET
Chemistry
Oxidation Number
The incorrect statement in respect of Chromyl chloride test is
KCET - 2009
KCET
Chemistry
d block elements
Argon is used:
KCET - 2009
KCET
Chemistry
p -Block Elements
The reaction involved in the oil of winter green test is salicylic acid
−
>
[
Δ
]
[
Conc.
H
2
S
O
4
]
{->[{\Delta}][{\text { Conc. } H _{2} SO _{4}}]}
−
>
[
Δ
]
[
Conc.
H
2
S
O
4
]
product. The product is treated with
N
a
2
C
O
3
Na _{2} CO _{3}
N
a
2
C
O
3
solution. The missing reagent in the above reaction is
KCET - 2009
KCET
Chemistry
Chemical Reactions
The carbon-carbon bond length in Benzene is
KCET - 2009
KCET
Chemistry
Properties of benzene
C
H
3
C
O
O
H
−
>
[
L
i
A
/
H
4
]
X
−
>
[
C
u
]
[
30
0
∘
C
]
Y
−
>
[
d
i
l
u
t
e
]
[
N
a
O
H
]
Z
{CH_3COOH ->[LiA/H_4] X ->[Cu][300 ^{\circ}C] Y ->[dilute][NaOH] Z}
C
H
3
COO
H
−
>
[
L
i
A
/
H
4
]
X
−
>
[
C
u
]
[
30
0
∘
C
]
Y
−
>
[
d
i
l
u
t
e
]
[
N
a
O
H
]
Z
In the above reaction
Z
Z
Z
is
KCET - 2009
KCET
Chemistry
Aldehydes, Ketones and Carboxylic Acids
A compound of
′
A
′
'A'
′
A
′
and
′
B
′
'B'
′
B
′
crystallises in a cubic lattice in which the
′
A
′
'A'
′
A
′
atoms occupy the lattice points at the corners of the cube. The
′
B
′
'B'
′
B
′
atoms occupy the centre of each face of the cube. The probable empirical formula of the compound is
KCET - 2009
KCET
Chemistry
The solid state
A 6% solution of urea is isotonic with
KCET - 2009
KCET
Chemistry
Solutions
In the electrolysis of acidulated water, it is desired to obtain
1.12
c
c
1.12\, cc
1.12
cc
of Hydrogen per second under
S
.
T
.
P
.
S.T.P.
S
.
T
.
P
.
condition. The current to be passed is
KCET - 2009
KCET
Chemistry
Electrochemistry
1
0
−
6
M
N
a
O
H
10^{-6}\, M\, NaOH
1
0
−
6
M
N
a
O
H
is diluted
100
100
100
times. The
p
H
pH
p
H
of the diluted base is
KCET - 2009
KCET
Chemistry
Equilibrium
Prev
1
...
429
430
431
432
433
...
764
Next