The standard enthalpy of formation $$\Delta _fH^o$$ at 298 K for methane, CH4(g), is –74.8 kJ mol–1. The additional information required to determine the average energy for C – H bond formation would be :
Answer
(A)
the dissociation energy of H2 and enthalpy of sublimation of carbon
2
An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If Ti is the
initial temperature and Tf is the final temperature, which of the following statements is correct?
Answer
(A)
(Tf)irrev > (Tf)rev
3
The enthalpy changes for the following processes are listed below :
Given that the standard states for iodine and chlorine are I2(s) and Cl2(g), the standard enthalpy of
formation for ICl(g) is :
Answer
(C)
+16.8 kJ mol–1
4
($$\Delta H - \Delta U$$) for the formation of carbon monoxide (CO) from its elements at 298 K is : (R = 8.314 J K–1 mol–1)
Answer
(B)
1238.78 J mol–1
5
Phosphorus pentachloride dissociates as follows, in a closed reaction vessel
PCl5 (g) $$\leftrightharpoons$$ PCl3 (g) + Cl2 (g)
If total pressure at equilibrium of the reaction mixture is P and degree of dissociation of PCl5 is x, the
partial pressure of PCl3 will be
Answer
(A)
$$\left( {{x \over {x + 1}}} \right)P$$
6
The equilibrium constant for the reaction
SO3 (g) $$\leftrightharpoons$$ SO2 (g) + $$1 \over 2$$ O2 (g)
is Kc = 4.9 $$\times$$ 10–2. The value of Kc for the reaction
2SO2 (g) + O2 (g) $$\leftrightharpoons$$ 2SO3 (g) will be :
Answer
(A)
416
7
Given the data at 25oC,
Ag + I- $$\to$$ AgI + e- , Eo = 0.152 V
Ag $$\to$$ Ag+ + e-, Eo = -0.800 V
What is the value of log Ksp for AgI? (2.303 RT/F = 0.059 V)
Answer
(D)
–16.13
8
CH3Br + Nu- $$\to$$ CH3 - Nu + Br- The decreasing order of the rate of the above reaction with nucleophiles (Nu–) A to D is
[Nu– = (A) PhO–, (B) AcO–, (C) HO–, (D) CH3O–]
Answer
(C)
D > C > A > B
9
The increasing order of stability of the following free radicals is
Increasing order of stability among the three main conformations (i.e. Eclipse, Anti, Gauche) of
2-fluoroethanol is
Answer
(C)
Eclipse, Anti, Gauche
11
CH3Br + Nu- $$\to$$ CH3 - Nu + Br- The decreasing order of the rate of the above reaction with nucleophiles (Nu–) A to D is
[Nu– = (A) PhO–, (B) AcO–, (C) HO–, (D) CH3O–]
Answer
(C)
D > C > A > B
12
How many EDTA (ethylenediaminetetraacetic acid) molecules are required to make an octahedral
complex with a Ca2+ ion?
Answer
(C)
One
13
Phenyl magnesium bromide reacts with methanol to give
Answer
(B)
a mixture of benzene and Mg(OMe)Br
14
Fluorobenzene (C6H5F) can be synthesized in the laboratory
Answer
(B)
from aniline by diazotisation followed by heating the diazonium salt with HBF4
15
Reaction of trans-2-phenyl-1-bromocyclopentane on reaction with alcoholic KOH produces
Answer
(D)
3-phenylcyclopentene
16
HBr reacts with CH2 = CH – OCH3 under anhydrous conditions at room temperature to give
Answer
(D)
H3C – CHBr – OCH3
17
The term anomers of glucose refers to
Answer
(D)
isomers of glucose that differ in configuration at carbon one (C-1)
18
The pyrimidine bases present in DNA are
Answer
(C)
cytosine and thymine
19
In Fe(CO)5, the Fe – C bond possesses :
Answer
(B)
both $$\sigma$$ and π characters
20
The $$IUPAC$$ name of the compound shown below is :
Answer
(A)
$$3$$-bromo - $$1$$-chlorocyclohexene
21
The alkene formed as a major product in the above elimination reaction is
Answer
(B)
22
The structure of the major product formed in the following reaction
is
Answer
(B)
23
The structure of the compound that gives a tribromo derivative on treatment with bromine water is
Answer
(C)
24
The electrophile involved in the above reaction is
Answer
(D)
25
Among the following the one that gives positives iodoform test upon reaction with $${I_2}$$ and $$NaOH$$ is
Answer
(B)
$$PhCHOHC{H_3}$$
26
The correct order of increasing acid strength of the compounds
Answer
(A)
$$D < A < B < C$$
27
A metal, $$M$$ forms chlorides in its $$+2$$ and $$+4$$ oxidation states. Which of the following statements about these chlorides is correct?
Answer
(A)
$$MC{l_2}$$ is more ionic than $$MC{l_4}$$
28
Rate of a reaction can be expressed by Arrhenius equation as:
$$$k = A\,{e^{ - E/RT}}$$$
In this equation, E represents
Answer
(A)
the energy above which all the colliding molecules will react
29
Among the following mixtures, dipole-dipole as the major interaction, is present in
Answer
(B)
acetonitrile and acetone
30
18 g of glucose (C6H12O6) is added to 178.2 g of water. The vapour pressure of water for this aqueous solution at 100oC is
Answer
(D)
752.40 Torr
31
The molar conductivities $$ \wedge _{NaOAc}^o$$ and $$ \wedge _{HCl}^o$$ and at infinite dilution in water at 25oC are 91.0 and 426.2 Scm2/mol respectively. To calculate $$ \wedge _{HOAc}^o$$ , the additional value required is
Answer
(D)
$$ \wedge _{NaCl}^o$$
32
Which of the following chemical reactions depicts the oxidizing behaviour of H2SO4?
Answer
(C)
2HI + H2SO4 $$\to$$ I2 + SO2 + 2H2O
33
Resistance of a conductivity cell filled with a solution of an electrolyte of concentration 0.1 M is 100$$\Omega $$.
The conductivity of this solution is 1.29 S m–1. Resistance of the same cell when filled with 0.2 M of
the same solution is 520 $$\Omega $$, The molar conductivity of 0.02 M solution of the electrolyte will be
Answer
(D)
12.4 $$\times$$ 10–4 S m2 mol–1
34
A reaction was found to be second order with respect to the concentration of carbon monoxide. If the
concentration of carbon monoxide is doubled, with everything else kept the same, the rate of reaction
will
Answer
(C)
increase by a factor of 4
35
In the transformation of $${}_{92}^{238}U$$ to $${}_{92}^{234}U$$, if one emission is an α-particle, what should be the other
emission(s)?
Answer
(A)
Two $$\beta^-$$
36
The following mechanism has been proposed for the reaction of NO with Br2 to form NOBr:
NO(g) + Br2 (g) $$\leftrightharpoons$$ NOBr2 (g)
NOBr2 (g) + NO (g) $$\to$$ 2NOBr (g)
If the second step is the rate determining step, the order of the reaction with respect to NO(g) is
Answer
(D)
2
37
The increasing order of the first ionization enthalpies of the elements B, P, S and F (lowest first) is :
Answer
(D)
B < S < P < F
38
Which of the following statements is true?
Answer
(D)
HNO3 is a stronger acid than HNO2
39
The “spin-only” magnetic moment [in units of Bohr magneton, (µB)] of Ni2+ in aqueous solution would
be : (Atomic number of Ni = 28)
Answer
(A)
2.84
40
Lanthanoid contraction is caused due to :
Answer
(D)
the imperfect shielding on outer electrons by 4f electrons from the nuclear charge
41
Nickel (Z = 28) combines with a uninegative monodentate ligand X– to form a paramagnetic complex [NiX4]2− . The number of unpaired electron(s) in the nickel and geometry of this complex ion are,
respectively
Answer
(B)
two, tetrahedral
42
How many moles of magnesium phosphate Mg3(PO4)2 will contain 0.25 mole of oxygen atoms?
Answer
(D)
3.125 $$\times$$ 10-2
43
Density of a 2.05M solution of acetic acid in water is 1.02 g/mL The molality of the solution is
Answer
(A)
2.28 mol kg-1
44
Uncertainty in the position of an electron (mass = 9.1 $$\times$$ 10-31 kg) moving with a velocity 300 ms-1, accurate upto 0.001% will be (h = 6.63 $$\times$$ 10-34 Js)
Answer
(A)
1.92 $$\times$$ 10-2 m
45
Uncertainty in the position of an electron (mass = 9.1 $$\times$$ 10-31 kg) moving with a velocity 300 ms-1, accurate upto 0.001% will be (h = 6.63 $$\times$$ 10-34 Js)
Answer
(A)
1.92 $$\times$$ 10-2 m
46
According to Bohr's theory, the angular momentum of an electron in 5th orbit is
Answer
(B)
2.5 $$h/\pi$$
47
Which of the following sets of ions represents a collection of isoelectronic species?
Answer
(C)
K+, Cl-, Ca2+, Sc3+
48
Following statements regarding the periodic trends of chemical reactivity of the alkali metals and the
halogens are given. Which of these statements gives the correct picture?
Answer
(D)
In alkali metals the reactivity increases but in the halogens it decreases with increase in atomic
number down the group
49
Which of the following molecules/ions does not contain unpaired electrons?
Answer
(A)
$$O_2^{2−} $$
50
In which of the following molecules/ions are all the bonds not equal?
Answer
(C)
SF4
51
The decreasing values of bond angles from NH3 (106o) to SbH3 (91o
) down group-15 of the periodic table is due to
