The compound formed as a result of oxidation of ethyl benzene by KMnO4 is :
คำตอบ
(C)
benzoic acid
2
Which one of the following conformation of cyclohexane is chiral?
คำตอบ
(A)
Twist boat
3
Presence of a nitro group in a benzene ring
คำตอบ
(D)
deactivates the ring towards electrophilic substitution
4
In a sautrated solution of the sparingly soluble strong electrolyte AgIO3 (Molecular mass = 283) the
equilibrium which sets in is
AgIO3(s) $$\leftrightharpoons$$ Ag+(aq) + $$IO_3^-$$
If the solubility product constant Ksp of AgIO3 at a given temperature is 1.0 $$\times$$10−8, what is the mass of AgIO3 contained in 100 ml of its saturated solution?
คำตอบ
(B)
2.83 × 10−3 g
5
The pKa of a weak acid (HA) is 4.5. The pOH of an aqueous buffered solution of HA in which 50% of
the acid is ionized is :
คำตอบ
(D)
9.5
6
The first and second dissociation constants of an acid H2A are 1.0 $$\times$$ 10−5
and 5.0 $$\times$$ 10−10 respectively. The overall dissociation constant of the acid will be :
คำตอบ
(C)
5.0 $$\times$$ 10−15
7
Identify the correct statement regarding a spontaneous process :
คำตอบ
(A)
For a spontaneous process in an isolated system, the change in entropy is positive
8
In conversion of lime-stone to lime,
CaCO3(s) $$\to$$ CaO(s) + CO2 (g) the vales of ∆H° and ∆S° are +179.1 kJ mol−1
and 160.2 J/K respectively at 298 K and 1 bar.
Assuming that ∆H° do not change with temperature, temperature above which conversion of
limestone to lime will be spontaneous is :
คำตอบ
(D)
1118 K
9
The reaction of toluene with Cl2 in presence of FeCl3 gives predominantly
คำตอบ
(C)
o-and p-chlorotoluene
10
The actinoids exhibits more number of oxidation states in general than the lanthanoids. This is
because :
คำตอบ
(D)
the 5f orbitals extend further from the nucleus than the 4f orbitals
11
The stability of dihalides of $$Si,Ge,Sn$$ and $$Pb$$ increases steadily in the sequence :
คำตอบ
(D)
$$Si{X_2} < < Ge{X_2} < < Sn{X_2} < < Pb{X_2}$$
12
คำตอบ
(A)
$$3$$ - enthyl - $$4$$ - $$4$$ - dimethylheptane
13
Which of the following molecules is expected to rotate the plane of plane - polarized light?
คำตอบ
(B)
14
Assuming that water vapour is an ideal gas, the internal energy change $$\left( {\Delta U} \right)$$ when $$1$$ mol of water is vapourised at $$1$$ bar pressure and $${100^ \circ }C$$ (Given : molar enthalpy of vapourisation of water at $$1$$ bar and $$373$$ $$K$$ $$ = 41\,kJ\,mo{l^{ - 1}}\,$$
and $$R = 8.3\,J\,mo{l^{ - 1}}\,{K^{ - 1}}$$ )
คำตอบ
(D)
$$37.904\,kJ\,mo{l^{ - 1}}$$
15
The secondary structure of a protein refers to
คำตอบ
(A)
$$\alpha$$-helical backbone
16
In the chemical reaction,
CH3CH2NH2 + CHCl3 + 3KOH $$\to$$ (A) + (B) + 3H2O, the compound (A) and (B) are respectively
คำตอบ
(D)
C2H5NC and 3KCl
17
Which one of the following is the strongest base in aqueous solution?
คำตอบ
(C)
Dimethylamine
18
In the following sequence of reactions,
CH3CH2OH $$\buildrel {P + {I_2}} \over
\longrightarrow $$ A $$\mathrel{\mathop{\kern0pt\longrightarrow}
\limits_{ether}^{Mg}} $$ B $$\buildrel {HCHO} \over
\longrightarrow $$ C $$\buildrel {{H_2}O} \over
\longrightarrow $$ D
the compound ‘D’ is
คำตอบ
(C)
n-propyl alcohol
19
Which of the following is the correct order of decreasing SN2 reactivity?
คำตอบ
(B)
RCH2X > R2CHX >
R3CX
20
Which one of the following has a square planar geometry?
คำตอบ
(D)
[PtCl4]2-
21
Identify the incorrect statement among the following :
คำตอบ
(D)
4f and 5f orbitals are equally shielded
22
Regular use of which of the following fertilizer increases the acidity of soil?
คำตอบ
(D)
Ammonium sulphate
23
Which of the following nuclear reactions will generate an isotope?
คำตอบ
(A)
neutron particle emission
24
A radioactive element gets spilled over the floor of a room. Its half-life period is 30 days. If the initial
activity is ten times the permissible value, after how many days will it be safe to enter the room?
คำตอบ
(D)
100 days
25
Consider the reaction, 2A + B $$\to$$ products. When concentration of B alone was doubled, the half-life did not change. When the concentration of A
alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is
คำตอบ
(A)
L mol-1 s-1
26
The energies of activation for forward and reverse reactions for A2 + B2 $$\leftrightharpoons$$ 2AB are 180 kJ mol−1
and 200 kJ mol−1 respectively. The presence of catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol−1. The enthalpy change of the reaction ( A2 + B2 $$\to$$ 2AB) in the presence of catalyst will be (in kJ mol−1)
คำตอบ
(D)
20
27
The cell, Zn | Zn2+ (1M) || Cu2+ (1M) | Cu($$E_{cell}^o$$ = 1.10V) was allowed to be completely discharged at 298 K. The relative concentration of Zn2+ to Cu2+ $$\left[ {{{\left[ {Z{n^{2 + }}} \right]} \over {\left[ {C{u^{2 + }}} \right]}}} \right]$$ is
คำตอบ
(C)
1037.3
28
The equivalent conductances of two strong electrolytes at infinite dilution in H2O (where ions move
freely through a solution) at 25oC are given below:
$$ \wedge _{C{H_3}COONa}^o$$ = 91.0 S cm2/equiv
$$ \wedge _{HCl}^o$$ = 426.2 S cm2/equiv
What additional information/quantity one needs to calculate $$ \wedge ^o$$ of an aqueous solution of acetic acid?
คำตอบ
(B)
$$ \wedge ^o$$ of NaCl
29
A mixture of ethyl alcohol and propyl alcohol has a vapour pressure of 290 mm at 300 K. The vapour
pressure of propyl alcohol is 200 mm. If the mole fraction of ethyl alcohol is 0.6, its vapour pressure
(in mm) at the same temperature will be
คำตอบ
(B)
350
30
A 5.25 % solution of a substance is isotonic with a 1.5% solution of urea (molar mass = 60 g mol−1) in
the same solvent. If the densities of both the solutions are assumed to be equal to 1.0 g cm−3, molar mass of the substance will be
คำตอบ
(D)
210.0 g mol−1
31
Which of the following reactions will yield 2, 2-dibromopropane?
คำตอบ
(B)
CH3 - C $$\equiv$$ CH + 2HBr $$\to$$
32
Which of the following hydrogen bonds is the strongest?
คำตอบ
(B)
F−H…….F
33
In which of the following ionization processes, the bond order has increased and the magnetic
behaviour has changed?
คำตอบ
(C)
$$NO \to NO^+$$
34
The charge/size ratio of a cation determines its polarizing power. Which one of the following
sequences represents the increasing order of the polarizinig order of the polarizing power of the
cationic species, K+, Ca2+, Mg2+, Be2+?
คำตอบ
(B)
K+ < Ca2+ < Mg2+ < Be2+
35
Which of the following species exhibits the diamagnetic behaviour?
คำตอบ
(A)
$$O_2^{2−}$$
36
Which of the following sets of quantum numbers represents the highest energy of an atom?
11.2 L H2(g) at STP is produced for every mole HCl(aq) consumed
38
The average marks of boys in a class is 52 and that of girls is 42. The average marks of boys
and girls combined is 50. The percentage of boys in the class is
