ASIAN INSTITUTE OF TECHNOLOGY
AIT UNDERGRADUATE ADMISSION TEST
SCHOOL OF ENGINEERING AND TECHNOLOGY
Time: 1.5 hours
CHEMISTRY
Admission Test
Additional materials:
The Periodic Table
FOLLOW THE INSTRUCTIONS GIVEN BELOW
The paper consists of two sections. Attempt all the sections as instructed below.
Section A
There are 30 multiple choice questions in this section. Answer all questions. You
are advised to spend 30 minutes on this section. Write down only the correct
answer in front of the question number on your answer booklet for this section.
Section B
Answer any three questions out of five questions. You are advised to spend 1.0
hours for this section. Show all the intermediate steps.
The use of a non-programmable electronic calculator is allowed.
1
Section A
1.
The 3d block element that shows the highest electrical conduction is
(1) Mn
2.
(3) Ni
(4) Cu
(5) Ti
The periods in the periodic table that contain elements found in all three physical states (solid,
liquid and gas ) at room temperature and atmospheric pressure are,
(1) 2 and 4
3.
(2) Co
(2) 3 and 4
(3) 3 and 6
(4) 4 and 5
(5) 4 and 6
The increasing order of boiling points of CO2, SO2, N2, He and Ne is,
(1) He < Ne < N2 < CO2 < SO2
(2) He < Ne < CO2 < N2 < SO2
(3) He < Ne < N2 < SO2 < CO2
(4) Ne < He < N2 < CO2 < SO2
(5) Ne < He < CO2 < SO2 < N2
4.
Which of the following is the strongest reducing agent in the gas phase ?
(1) Al
5.
(4) H2
(5) F2
(2) Br and Be
(3) Hg and Br
(4) Hg and Xe
(5) Se and Br
Which molecule or ion from those given below has the highest dipole moment ?
(1) O3
7.
(3) Zn
The two elements which are liquids at room temperature are
(1) Li and Be
6.
(2) Na
(2) NH3
(3) NO2+
(4) AlCl3
(5) ICl4-
Equal volumes of HNO3 of pH = 2.0 and of HCl of pH = 1.0 were mixed. The pH of the mixture is,
(1) 1.0
(2) 1.3
(3) 1.5
(4) 2.0
2
(5) 3.0
8.
9.
The shape of the Cl2CO molecule is
(1) Trigonal planar
(2) Square pyramidal
(4) Tetrahedral
(5) None of these
Identify the molecule or ion from those given below whose shape is distinctly different from
that SO32 ion.
(1) ClO3
10.
(3) Octahedral
-
(2) PCl3
(3) SOCl2
(4) H3O
+
(5) NO3
-
An aqueous solution of Ca(NO3)2 contains 20 mg of Ca2+ ions in 0.500 dm3. The concentratration
of nitrate ions in the solution ( in mol dm-3) is, (Ca = 40)
(1) 5.0 × 10-4
(2) 1.0 × 10-3
(3) 2.0 × 10-3
(4) 4.0 × 10-3
-2
(5) 1.0 × 10
11.
At a temperature of 300K and under a pressure of 1 atmosphere, which is the gas that is most
likely to have a density nearest to that of N2 ?
(relative atomic masses : H = 1; C = 12; N = 14; O = 16; F = 19)
(1) O2
12.
(2) NO
(3) CO2
(4) CH3F
(5) C2H4
The IUPAC name of the following compound is,
CO2H
CH3 CH
CH
CH
CH
CH3
CH3
(2) 1,2-dimethylpent-3-enoic acid
(2) 3-methylhex-4-en-2-oic acid
(3) 4,5-dimethyl-2-hexenoic acid
(4) 2,3-dimethyl-4-hexenoic acid
(5) none of these
3
13.
An HCl solution contains 36.5% by mass of HCl. The density of the solution is 1.15 g cm -3. What is
the concentration of HCl in the solution, in units of mol dm -3 ?
(relative atomic masses : H = 1;
(1) 0.869
14.
Cl = 35.5)
(2) 1.15
(3) 11.5
(4) 115
(5) 8.69
The increasing order of the rate at which the following compounds undergo nitration is,
NO2
OH
CH3
A
B
C
D
(1) A < C < D < B
(2) A < D < C < B
(3) A < D < B < C
(4) D < A < C < B
(5) D < C < A < B
15.
A certain salt dissolves in water and gives a coloured solution. When dil. NaOH is added to this
solution, a pale green precipitate is formed. When NH 4OH is added to this precipitate, it
dissolves forming a blue solution. The cation present in the salt is,
2+
(1) Co
16.
2+
(3) Fe
2+
(4) Fe
3+
3+
(5) Cr
A solution of Na2SO4 has been prepared by dissolving 142 mg of pure Na2SO4 in water, in a 500
cm3 volumetric flask and by diluting up to the mark. The Na+ ion content in mg dm-3 units in this
solution is,
( O = 16.0, Na = 23.0, S =32.0)
(1) 2.00 × 10-3
17.
(2) Ni
(2) 4.00 × 10-3
(3) 46
(4) 92
(5) 184
Which one of the following is not used for dehydration reactions ?
(1) H3PO4
(2) H2SO4
(3) Al2O3
4
(4) P2O5
(5) alcoholic KOH
18.
The oxidation number of nitrogen and sulphur atoms in the following ion are respectively,
H
..
N
H
(1) -3 and +2
19.
2) -3 and +6
.O.
S
.O..._
..
..
O
(3) -3 and +4
(4) +1 and +4
(5) +3 and +6
The equilibrium constants at a particular temperature of the reactions,
A (g)
2B (g)
and
B (g)
C(g) + D(g)
are K1 and K2, respectively. The equilibrium constant of the reactions,
A (g)
2C (g) + 2D(g)
at the same temperature is,
20.
(1) K1+ K2
(2) K1 K2
(4) 2K1 K2
(5) K1+ 2K2
(3) K1 K2
2
Which one of the following cannot be used to distinguish between
N H2
OH
and
(1) Br2 water
(2) NaOH solution
(3) Neutral FeCl3 solution
(4) HNO2 solution
(5) Moist blue litmus paper
21.
The percentage ionization of an aqueous solution of 0.10 mol dm -3 HCOOH at 25°C is,
( Ka of HCOOH at 25°C = 1.7 × 10-4 mol dm-3 )
(1) 0.4
(2) 2
(3) 4
(4) 10
5
(5) 40
22.
23.
In which of the following do the two molecules have unpaired electron each ?
(1) SO2 and NO
(2) NO and CO
(4) NO2 and N2O
(5) SO2 and NO2
(3) NO and NO2
-34
The energy of 1 mol of photons with wave-length 305 nm is, (Planck constant = 6.62 × 10
8
J s,
-1
speed of light = 3.00 × 10 ms )
(1) 256 kJ
24.
25.
26.
(2) 302 kJ
(3) 392 kJ
(4) 452 kJ
(5) 512 kJ
The enthalpy change of which of the following chemical reactions corresponds to the standard
enthalpy of formation of CaO(s) ?
(1) Ca2+ (g) + O2- (g)
CaO(s)
(2) Ca (g) + ½ O2(g)
CaO(s)
(3) Ca (s) + O(g)
CaO(s)
(4) 2Ca (s) + O2(g)
2 CaO(s)
(5) Ca (s) + ½ O2(g)
CaO(s)
A 30.0 mg sample of a volatile liquid is vaporized at 127°C. The volume of the vapour phase
measured at 1.00 × 105 Pa is 16.65 cm3. If the vapour phase behaves ideally, the liquid is most
likely to be (H =1.0, C = 12.0, O =16.0, Cl =35.5 )
(1) methanol
(2) ethanol
(3) acetone
(4) chloroform
(5) carbon tetrachloride
The energy released in the process
X (g)
(1) Li
X (g) is lowest when X is
+ e
(2) Be
(3) B
(4) C
6
(5) F
27.
A student prepared an electrochemical cell by inserting a Cu rod in an aqueous CuSO4 solution, a
Ag rod in an aquous AgNO3 solution and marking electrical contact between the solutions using
a salt bridge. A representation of the cell in standard notation is
(1) Cu2+ (aq) / Cu (s) ǁ Ag (s) /Ag+ (aq)
(2) Cu (s) / Cu2+ (aq) ǁ Ag (s) /Ag+ (aq)
(3) Cu2+ (aq) / Cu (s) ǁ Ag+ (aq) /Ag(s)
(4) Cu (s) / Cu2+ (aq) ǁ Ag+ (aq) /Ag(s)
(5) not possible since the electrodes on the right and left hand sides are not given.
28.
Which of the following statement is not true regarding H2O2 ?
(1) H2O2 disproportionates when heated.
(2) In acid medium, Fe2+ ions reduce H2O2 to H2O
(3) AgO oxidizes H2O2 to O2
(4) H2O2 is used as an antiseptic
(5) The dipole moment of H2O2 is zero.
29.
30.
Which of the following gases will react with an aqueous solution of FeBr3 ?
(A) SO2
(B) CO2
(1) A and B
(2) A, B and C
(C) H2S
(D) Cl2
(3) A, C and D
(4) C and D
(5) A, B and D
The salt X dissolves in dil. HCl forming a colourless solution. This solution
(i) gives a white precipitate when diluted with water
(ii) gives a black precipitate when H2S is passed.
The cation present in X is
(1) Cu2+
(2) Bi3+
(3) Hg2+
(4) Sb3+
7
(5) As3+
Section B
Question 1
(a)
The 3d transition element M shows the highest oxidation state of +7
i)
(b)
Identify M
ii)
Write the complete electronic configuration of M.
iii)
Give the chemical formulae and the colour of the most stable oxide of M.
The first four electronic energy levels of the hydrogen atom are represented in the diagram
given below.
n = 4
n = 3
n = 2
n = 1
(A) Infra- red
Name of
series
………………………………..
(B) Visible
……………………………………
(C) Ultra- violet
………………………………
Indicate with arrows all electronic transitions that could occur between the above energy levels
and which are responsible for emission lines in (A) the infra-red region (B) the visible region and
(C) the ultra- violet region.
Write the names of the series to which each set of lines belongs, in the space provided in the
diagram.
8
(c)
Y and Z are two non-transition elements belonging to the same group of the periodic table. They
form the compounds YZ2 and YZ3.
i)
Identify the elements Y and Z.
Y = ……………………………………. ,
ii)
Z = ………………………………………
Name the shapes of the molecules YZ2 and YZ3. (diagrams are not acceptable.)
YZ2 = ………………………………….. ,
YZ3 = ………………………………………
9
Question 2
(a)
You are provided with the following list of components
KIO3
PCl5
CdCl2
Co(NO3)2
Na2S2O3
Which one of the above compounds,
(b)
i)
Is used as a primary stand in volumetric analysis?
ii)
Gives a pale yellow precipitate when dil. H2SO4 is added to its aqueous solution?
iii)
Undergoes hydrolysis to give an acid with a tetrahedral structure?
iv)
Gives a dark yellow precipitate when dissolved in dil. HCl and H 2S is passed through the
solution?
v)
Gives a blue colored solution on addition of conc.HCl to its aqueous solution?
i)
+
Calculate the concentration of H ions in solution when a sample of 4.00g of pure CaCO3
3
-3
is allowed to react with 500.0 cm of 0.30 mol dm HCl solution. (Relative molar mass of
CaCO3 =100)
-3
3
ii)
250.0 cm3 of 0.16 mol dm NaOH solution is added to 250.0 cm of the solution
obtained in step (i) above, maintaining the temperature at 25°C. Show that no
precipitation occurs. Solubility product of Ca(OH)2 at 25°C is 6.5 × 10-6 mol3 dm-9.
iii)
Calculate the minimum mass of solid Ca(NO3)2 that should be added to the solution
obtained in step (ii) above in order to observe a precipitation in it, while maintaining the
temperature at 25°C. (N =14, O =16, Ca = 40)
Note: Assume that there are no volume changes during mixing of solutions)
10
Question 3
(a)
An industrially important Organic compound X, contains carbon, hydrogen and oxygen only.
i)
Write balance chemical equation for the complete combustion of X taking its molecular
formula as CxHyOz
ii)
The combustion of 62 mg of X (relative molecular mass Mr = 62) gives 88 mg of CO2
and 54 mg of H2O. Deduce values for x, y and z in the molecular formula C xHyOz.
( C = 12.0, H =1.0, O = 16.0 )
iii)
(b)
The reaction of 62 mg of X with sodium gives 2 mg of hydrogen gas. Deduce the
structure of X.
Complete the following reaction scheme, by writing the structures of compounds in the boxes
and the reagents in circles.
CH2CH3
O
CH3CH2
C
11
NO2
Question 4
(a)
Calculate the lattice energy of CaBr2 (s) by constrcting an appropriate enthalpy level diagram.
Necessary thermochemical data are given below. (Physical state of all chemical specie must be
given for full marks. )
Enthalpy of evaporation of Br (l)
=
Bond dissociation enthalpy of Br2 (g)
=
Electron affinity of Br (g)
=
Enthalpy of atomization of Ca (s)
=
Sum of first and second ionization energies of Ca (g)=
Enthalpy of formation of CaBr2 (s)
=
(b)
(i)
31 kJ mol-1
193 kJ mol-1
-331 kJ mol-1
177 kJ mol-1
1740 kJ mol-1
-683 kJ mol-1
The density of an aqueous solution prepared using pure Na2CO3 was found to be 1.0212
g cm-3. Calculate the concentration of this solution.
Assume that the density of water at the very same temperature is 1.000 g cm -3 and that
there is no change in volume during the dissolution of Na 2CO3.
(c)
(ii)
With the solution in (i) above (in the burette) 25.00 cm3 aliquots of a H2SO4 solution
were titrated using phenolphthalein as the indicator. The average of appropriate end
point obtained was 12.50 cm3. Calculate the concentration of the H2SO4 solution.
(iii)
Would it be possible to carry out the above titration in the same way using methyl
orange as the indicator ? If yes, what is the end- point you expect ? If no, give reasons.
(Na = 23.0, C = 12.0, O = 16.0 )
Photochemical smog is a major atmospheric pollution problem associated with industrialization
and transportation along with specific climatic conditions.
i)
Explain how photochemical smog develops.
ii)
Indicate how you would become aware of the presence of photochemical smog.
iii)
List four major toxic products found in photochemical smog.
iv)
Give three adverse effects due to photochemical smog.
12
Question 5
Salt-bridge
(a)
Mg rod
Cu rod
CuSO4 (aq)
MgCl2 (aq)
(1.0 mol dm-3)
-3
(1.0 mol dm )
Cell A
At 25°C,
E° Mg2+ (aq) / Mg (s)
= -2.37 V
E° Cu2+ (aq) /Cu (s)
= 0.34 V
Question (i) to (iii) relate to electrochemical cell A.
(b)
i)
Calculate the electromotive force (e.m.f) of the cell.
ii)
State whether the cell e.m.f. would change, if a 1.0 moldm -3 MgSO4 solution was used
instead of 1.0 moldm-3 MgCl2 solution in the cell. Explain your answer, briefly.
iii)
What is the function of the salt bridge?
Give an example of a compound that can be used to prepare the salt-bridge.
A sample of P gas was heated up to 481 K in a rigid container of volume 1.0 dm3 in order to
reach the following equilibrium.
2P(g)
2Q (g) + R(g)
At equilibrium, it was found that the total pressure of the system was 1.2 × 105 Pa and that the
partial pressure of R(g) was 2 × 104 Pa.
i)
Calculate the partial pressure of P(g) and Q(g).
ii)
Calculate the concentrations of P(g), Q(g) and R(g) at equilibrium.
iii)
Calculate the equilibrium constant, Kc for the above equilibrium.
( RT = 4.0 × 103 J mol-1 at 481 K )
13