JEE MAIN - Chemistry (2003)

1
Which one of the following statements is not true?
答え
(B)
The pH of 1 $$\times$$ 10^-8 M HCl is 8
2
The internal energy change when a system goes from state A to B is 40 kJ/mole. If the system goes from A to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy?
答え
(C)
Zero
3
In an irreversible process taking place at constant T and P and in which only pressure-volume work is being done, the change in Gibbs free energy (dG) and change in entropy (dS), satisfy the criteria :
答え
(A)
(dS)_{V, E} > 0, (dG)_{T, P} < 0
4
The enthalpy change for a reaction does not depend upon :
答え
(B)
the nature of intermediate reaction steps
5
The correct relationship between free energy change in a reaction and the corresponding equilibrium constant K_c is :
答え
(C)
- $$\Delta G^o$$ = RT ln K_c
6
If at 298 K the bond energies of C - H, C - C, C = C and H - H bonds are respectively 414, 347, 615 and 435 kJ/mol, the value of enthalpy change for the reaction
H₂C = CH₂(g) + H₂(g) $$\to$$ H₃C - CH₃(g) at 298 K will be :
答え
(C)
- 125 kJ
7
The solubility in water of a sparingly soluble salt AB₂ is 1.0 $$\times$$ 10^-5 mol L^-1. Its solubility product number will be :
答え
(D)
4 $$\times$$ 10^-15
8
Consider the reaction equilibrium
2 SO₂ (g) + O₂ (g) $$\leftrightharpoons$$ 2 SO₃ (g); $$\Delta H^o$$ = -198 kJ
One the basis of Le Chatelier's principle, the condition favourable for the forward reaction is :
答え
(B)
lowering the temperature and increasing the pressure
9
For the reaction equilibrium
N₂O₄ (g) $$\leftrightharpoons$$ 2NO₂ (g)
the concentrations of N₂O₄ and NO₂ at equilibrium are 4.8 $$\times$$ 10^-2 and 1.2 $$\times$$ 10^-2 mol L^-1 respectively. The value of K_c for the reaction is
答え
(B)
3 $$\times$$ 10^-3 mol L^-1
10
When rain is accompanied by a thunderstorm, the collected rain water will have a pH value :
答え
(D)
slightly lower than that of rain water without thunderstorm
11
The IUPAC name of CH₃COCH(CH₃)₂ is
答え
(C)
3-methyl-2-butaone
12
In the anion HCOO^$$-$$ the two carbon-oxygen bonds are found to be of equal length. What is the reason for it?
答え
(B)
The anion HCOO- has two resonating structures
13
The general formula C_nH_2nO₂ could be for open chain
答え
(A)
carboxylic acids
14
On mixing a certain alkane with chlorine and irradiating it with ultravioletlight, it forms only one monochloroalkane. This alkane could be
答え
(C)
neopentane
15
Butene-1 may be converted to butane by reaction with
答え
(C)
Pd/H₂
16
During dehydration of alcohols to alkenes by heating with conc. H₂SO₄ the initiation step is
答え
(D)
protonation of alcohol molecule
17
When CH₂ = CH - COOH is reduced with LiAlH₄, the compound obtained will be
答え
(A)
CH₂ = CH - CH₂OH
18
The correct order of increasing basic nature for the bases NH₃, CH₃NH₂ and (CH₃)₂ NH is
答え
(B)
NH₃ < CH₃NH₂ < (CH₃)₂NH
19
Ethyl isocyanide on hydrolysis in acidic medium generates
答え
(D)
ethylamine salt and methanoic acid
20
Complete hydrolysis of cellulose gives
答え
(B)
D-glucose
21
Which one of the following statements is correct?
答え
(A)
From a mixed precipitate of AgCl and AgI, ammonia solution dissolves only AgCl
22
Bottles containing C₆H₅l and C₆H₅CH₂I lost their original labels. They were labelled A and B for testing A and B were separately taken in test tubes and boiled with NaOH solution. The end solution in each tube was made acidic with dilute HNO₃ and then some AgNO₃ solution was added. Substance B gave a yellow precipitate. Which one of the following statements is true for this experiment?
答え
(D)
A was C₆H₅I
23
Among the following four structures $$i$$ to $$iv,$$

it is true that
答え
(A)
only $$i$$ and $$ii$$ are chiral compounds
24
The reduction in atomic size with increase in atomic number is a characteristic of elements of
答え
(D)
High atomic masses.
25
The atomic numbers of Vanadium (V), Chromium (cr), Manganese (Mn) and Iron (Fe), respectively, $$23,24,25$$ and $$26$$. Which one of these may be expected to have the higher second ionization enthalpy?
答え
(A)
Cr
26
The reaction of chloroform with alcoholic $$KOH$$ and p-toluidine forms
答え
(C)
27
The reason for double helical structure of $$DNA$$ is operation of
答え
(B)
hydrogen bonding
28
A red solid is insolvable in water. However it becomes soluble if some $$K{\rm I}$$ is added to water. Heating the red solid in a test tube results in liberation of some violet colored fumes and droplets of a metal appear on the cooler parts of the test tube. The red solid is :
答え
(A)
$$Hg{{\rm I}_2}$$
29
A pressure cooker reduces cooking time for food because
答え
(A)
boiling point of water involved in cooking is increased
30
In a 0.2 molal aqueous solution of a weak acid HX the degree of ionization is 0.3. Taking k_f for water as 1.85, the freezing point of the solution will be nearest to
答え
(D)
-0.480^oC
31
If liquids A and B form an ideal solution
答え
(D)
the enthalpy of mixing is zero
32
Standard reduction electrode potentials of three metals A,B&C are respectively +0.5 V, -3.0 V & -1.2 V. The reducing, powers of these metals are
答え
(D)
B > C > A
33
For a cell reaction involving a two-electron change, the standard e.m.f. of the cell is found to be 0.295 V at 25^oC. The equilibrium constant of the reaction at 25^oC will be
答え
(C)
1 $$\times$$ 10¹⁰
34
When during electrolysis of a solution of AgNO₃, 9650 coulombs of charge pass through the electroplating bath, the mass of silver deposited on the cathode will be :
答え
(A)
10.8 g
35
For the redox reaction Zn(s) + Cu²⁺(0.1 M) $$\to$$ Zn²⁺(1M) + Cu(s) taking place in a cell, $$E_{cell}^o$$ is 1.10 volt. E_cell for the cell will be ($$2.303{{RT} \over F}$$ = 0.0591)
答え
(B)
1.07 volt
36
Several blocks of magnesium are fixed to the bottom of a ship to :
答え
(B)
prevent action of water and salt
37
The radionucleide $${}_{90}^{234}Th$$ undergoes two successive $$\beta$$ -decays followed by one $$\alpha$$-decay. The atomic number and the mass number respectively of the resulting radionucleide are
答え
(B)
90 and 230
38
The half-life of a radioactive isotope is three hours. If the initial mass of the isotope were 256 g, the mass of it remaining undecayed after 18 hours would be
答え
(D)
4.0 g
39
In respect of the equation k = Ae^-E_a/RT in chemical kinetics, which one of the following statements is correct?
答え
(B)
E_a is energy of activation
40
The rate law for a reaction between the substances A and B is given by Rate = k[A]ⁿ [B]^m On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as
答え
(C)
2^{( n - m)}
41
For the reaction system:

2NO(g) + O₂(g) $$\to$$ 2NO₂(g) volume is suddenly reduce to half its value by increasing the pressure on it. If the reaction is of first order with respect to O₂ and second order with respect to NO, the rate of reaction will
答え
(B)
increase to eight times of its initial value
42
Which one of the following substances has the highest proton affinity?
答え
(B)
NH₃
43
For making good quality mirrors, plates of float glass are used. These are obtained by floating molten glass over a liquid metal which does not solidify before glass. The metal used can be :
答え
(D)
mercury
44
Glass is a :
答え
(A)
super-cooled liquid
45
What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid?
答え
(A)
$$Cr_2O^{2-}_7$$ and H₂O are formed
46
The atomic numbers of vanadium (V), Chromium (Cr), manganese (Mn) and iron (Fe) are respectively 23, 24, 25 and 26. Which one of these may be expected to have the highest second ionization enthalpy?
答え
(A)
Cr
47
Which one of the following nitrates will leave behind a metal on strong heating?
答え
(C)
Silver nitrate
48
Ammonia forms the complex ion [Cu(NH₃)₄]²⁺ with copper ions in alkaline solutions but not in acidic solutions. What is the reason for it?
答え
(A)
In acidic solutions protons coordinate with ammonia molecules forming $$NH^+_4$$ ions and NH₃ molecules are not available
49
The radius of La³⁺ (Atomic number of La = 57) is 1.06 Å. Which one of the following given values will be closest to the radius of Lu³⁺ (Atomic number of Lu = 71) ?
答え
(C)
0.85 Å
50
One mole of the complex compound Co(NH₃)₅Cl₃, gives 3 moles of ions on dissolution in water. One mole of the same complex reacts with two moles of AgNO₃ solution to yield two moles of AgCl (s). The structure of the complex is :
答え
(D)
[Co(NH₃)₅Cl] Cl₂
51
In the coordination compound, K₄[Ni(CN)₄], the oxidation state of nickel is :
答え
(A)
0
52
The pair of species having identical shapes for molecules of both species is
答え
(A)
XeF₂, CO₂
53
What volume of hydrogen gas at 273 K and 1 atm pressure will be consumed in obtaining 21.6 g of elemental boron (atomic mass = 10.8) from the reduction of boron trichloride by hydrogen?
答え
(A)
67.2 L
54
25 ml of a solution of barium hydroxide on titration with a 0.1 molar solution of hydrochloric acid gave a litre value of 35 ml. The molarity of barium hydroxide solution was
答え
(D)
0.07
55
The number of d-electrons retained in Fe²⁺ (At no of Fe = 26) ion is :
答え
(C)
6
56
The orbital angular momentum for an electron revolving in an orbit is given by $$\sqrt {l(l + 1)} {h \over {2\pi }}$$. This momentum for an s-electron will be given by
答え
(A)
zero
57
Which one of the following groupings represents a collection of isoelectronic species? (At. nos. : Cs : 55, Br : 35)
答え
(A)
N^3-, F^-, Na⁺
58
In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen
答え
(A)
5 $$\to$$ 2
59
The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 meters per second is approximately
答え
(D)
10^-33 meters
60
According to the Periodic Law of elements, the variation in properties of elements is related to their
答え
(B)
atomic numbers
61
Which one of the following is an amphoteric oxide?
答え
(D)
ZnO
62
An ethar is more volatile than an alcohol having the same molecular formula. This is due to
答え
(C)
inter-molecular hydrogen bonding in alcohols
63
Which one of the following pairs of molecules will have permanent dipole moments for both members
答え
(B)
NO₂ and O₃
64
Which one of the following compounds has the smallest bond angle in its molecule?
答え
(B)
SH₂