NSEC 2019 24th Nov Question Paper

NSEC 2019 24th Nov - Question 1

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The following qualitative plots depict the first, second and third ionization energies (I.E.) of Mg, Al and K. Among the following, the correct match of I.E. and the metal is

A

X-Al ; Y-Mg ; Z-K

B

X-Mg ; Y-Al ; Z-K

C

X-Mg ; Y-K ; Z-Al

D

X-Al; Y-K; Z-Mg

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NSEC 2019 24th Nov - Question 2

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A solid comprises of three types of elements, P, Q and R. P forms an FCC lattice in which Q and R occupy all the tetrahedral voids and half the octahedral voids respectively. The molecular formula of the solid is

A

$$\text{P}_2\text{Q}_4\text{R}$$

B

$$\text{PQ}_2\text{R}_4$$

C

$$\text{P}_4\text{Q}_2\text{R}$$

D

$$\text{P}_4\text{QR}$$

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NSEC 2019 24th Nov - Question 3

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The set in which all the species are diamagnetic is

A

$$\text{B}_2$$, $$\text{O}_2$$, NO

B

$$\text{O}_2$$, $$\text{O}_2^+$$, CO

C

$$\text{N}_2$$, $$\text{O}_2^-$$, $$\text{CN}^-$$

D

$$\text{C}_2$$, $$\text{O}_2^{2-}$$, $$\text{NO}^+$$

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NSEC 2019 24th Nov - Question 4

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The structure of compound X ($$\text{C}_8\text{H}_{11}\text{NO}$$) based on the following tests and observations is

A

B

C

D

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NSEC 2019 24th Nov - Question 5

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Reaction of $$\text{C}_6\text{H}_5\text{MgBr}$$ with phenol gives

A

B

C

D

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NSEC 2019 24th Nov - Question 6

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The work done (kJ) in the irreversible isothermal compression of 2.0 moles of an ideal gas from 1 bar to 100 bar at $$25^\circ\text{C}$$ at constant external pressure of 500 bar is

A

2452

B

490

C

2486

D

$$-490$$

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NSEC 2019 24th Nov - Question 7

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The power and wavelength emitted by a laser pointer commonly used in Power Point presentations are 1.0 mW and 670 nm respectively. Number of photons emitted by this pointer during a presentation of 5 minutes is

A

$$1.01 \times 10^9$$

B

$$1.01 \times 10^{21}$$

C

$$1.6 \times 10^{16}$$

D

$$1.01 \times 10^{18}$$

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NSEC 2019 24th Nov - Question 8

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The number of stereoisomers is maximum for

A

$$[\text{Co(en)}_3]^{3+}$$

B

$$[\text{Co(en)}_2\text{ClBr}]^+$$

C

$$[\text{Co(NH}_3)_4\text{Cl}_2]^+$$

D

$$[\text{Co(NH}_3)_4\text{ClBr}]^+$$

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NSEC 2019 24th Nov - Question 9

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Which of the following is NOT correct about hydrides?
I. Saline hydrides are stoichiometric and metallic hydrides are non-stoichiometric.
II. $$\text{BeH}_2$$ is monomeric whereas $$\text{MgH}_2$$ is polymeric.
III. Hydrides of the elements of Group 13 are electron deficient and those of Group 15 are electron rich.
IV. NaH reacts with water and liberates $$\text{H}_2$$ whereas $$\text{B}_2\text{H}_6$$ does not react with water.

A

IV only

B

I and III

C

III only

D

II and IV

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NSEC 2019 24th Nov - Question 10

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Atropine ($$\text{C}_{17}\text{H}_{23}\text{O}_3\text{N}$$) is a naturally occurring compound used to treat certain types of poisoning. The degree of unsaturation in atropine is

A

7

B

6

C

5

D

4

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NSEC 2019 24th Nov - Question 11

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The compounds X and Y formed in the following reaction are

A

hemiacetals with identical physical and chemical properties

B

acetals with identical physical and chemical properties

C

hemiacetals with different physical and chemical properties

D

acetals with different physical and chemical properties

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NSEC 2019 24th Nov - Question 12

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In which of the following, is a new C-C bond formed in the product?

A

I, III and IV

B

II and III

C

III only

D

III and IV

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NSEC 2019 24th Nov - Question 13

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Aqueous solution of slaked lime, $$\text{Ca(OH)}_2$$, is extensively used in municipal waste water treatment. Maximum pH possible in an aqueous solution of slaked lime is ($$K_{sp}$$ of $$\text{Ca(OH)}_2 = 5.5 \times 10^{-6}$$)

A

1.66

B

8.14

C

12.04

D

12.34

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NSEC 2019 24th Nov - Question 14

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An electron present in the third excited state of a H atom returns to the first excited state and then to the ground state. If $$\lambda_1$$ and $$\lambda_2$$ are the wavelengths of light emitted in these two transitions respectively, $$\lambda_1 \colon \lambda_2$$ is

A

$$4 \colon 1$$

B

$$5 \colon 9$$

C

$$3 \colon 1$$

D

$$2 \colon 1$$

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NSEC 2019 24th Nov - Question 15

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$$\text{MnCl}_2\cdot 4\text{H}_2\text{O}$$ (molar mass 198 g $$\text{mol}^{-1}$$) when dissolved in water forms a complex of $$\text{Mn}^{2+}$$. An aqueous solution containing 0.400 g of $$\text{MnCl}_2\cdot 4\text{H}_2\text{O}$$ was passed through a column of a cation exchange resin and the acid solution coming out was neutralized with 10 mL of 0.20 M NaOH. The formula of the complex formed is

A

$$[\text{Mn(H}_2\text{O})_4\text{Cl}_2]$$

B

$$[\text{Mn(H}_2\text{O})_6]\text{Cl}_2$$

C

$$[\text{Mn(H}_2\text{O})_5\text{Cl}]\text{Cl}$$

D

$$\text{Na}[\text{Mn(H}_2\text{O})_3\text{Cl}_3]$$

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NSEC 2019 24th Nov - Question 16

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IUPAC name of the following molecule is

A

4-hydroxyhept-2-en-5-yne

B

hept-2-en-5-yn-4-ol

C

hept-5-en-2-yn-4-ol

D

4-hydroxyhept-5-en-2-yne

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NSEC 2019 24th Nov - Question 17

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The product or products of the following reaction is or are

A

I and II

B

II

C

III

D

IV

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NSEC 2019 24th Nov - Question 18

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The percentage dissociation of 0.08 M aqueous acetic acid solution at $$25^\circ\text{C}$$ is ($$K_a$$ of acetic acid at $$25^\circ\text{C}$$ is $$1.8 \times 10^{-5}$$)

A

2.92

B

1.5

C

1.2

D

4.8

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NSEC 2019 24th Nov - Question 19

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For which of the following processes, carried out in free space, energy will be absorbed?
I. Separating an electron from an electron.
II. Removing an electron from a neutral atom.
III. Separating a proton from a proton.
IV. Separating an electron from a proton.

A

I only

B

II and IV

C

I and III

D

II only

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NSEC 2019 24th Nov - Question 20

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Decay of radioisotopes follows first order kinetics. Radioisotope $$\text{U}^{238}$$ undergoes decay to a stable isotope, $$\text{Th}^{234}$$. The ratio of the number of atoms of $$\text{U}^{238}$$ to that of $$\text{Th}^{234}$$ after three half lives is

A

$$\frac{1}{3}$$

B

$$\frac{3}{4}$$

C

$$\frac{1}{4}$$

D

$$\frac{1}{7}$$

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NSEC 2019 24th Nov - Question 21

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Myoglobin (Mb), an oxygen storage protein, contains 0.34 % Fe by mass and in each molecule of myoglobin one ion of Fe is present. Molar mass of Mb (g $$\text{mol}^{-1}$$) is (Molar mass of Fe is 55.845 g $$\text{mol}^{-1}$$)

A

16407

B

164206

C

16425

D

164250

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NSEC 2019 24th Nov - Question 22

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The following Ellingham diagram depicts the oxidation of C, CO and Fe. Which of the following is correct?

I. FeO can be reduced by C below 600 K.
II. FeO can be reduced by CO below 600 K.
III. FeO can be reduced by C above 1000 K.
IV. FeO can be reduced by CO above 1000 K.

A

II and III

B

I and IV

C

I and III

D

II and IV

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NSEC 2019 24th Nov - Question 23

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$$\text{N}^{3-}$$, $$\text{F}^-$$, $$\text{Na}^+$$ and $$\text{Mg}^{2+}$$ have the same number of electrons. Which of them will have the smallest and the largest ionic radii respectively?

A

$$\text{Mg}^{2+}$$ and $$\text{N}^{3-}$$

B

$$\text{Mg}^{2+}$$ and $$\text{Na}^+$$

C

$$\text{N}^{3-}$$ and $$\text{Na}^+$$

D

$$\text{F}^-$$ and $$\text{N}^{3-}$$

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NSEC 2019 24th Nov - Question 24

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The reaction of 2,4-hexadiene with one equivalent of bromine at $$0^\circ\text{C}$$ gives a mixture of two compounds X and Y. If X is 4,5-dibromohex-2-ene, Y is

A

2,5-dibromohex-2-ene

B

2,5-dibromohex-3-ene

C

2,3-dibromohex-3-ene

D

3,4-dibromohex-3-ene

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NSEC 2019 24th Nov - Question 25

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The major product of the following reaction is

A

B

C

D

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NSEC 2019 24th Nov - Question 26

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The kinetic energy of the photoelectrons ejected by a metal surface increased from 0.6 eV to 0.9 eV when the energy of the incident photons was increased by 20 %. The work function of the metal is

A

0.66 eV

B

0.72 eV

C

0.90 eV

D

0.30 eV

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NSEC 2019 24th Nov - Question 27

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An electrochemical cell was constructed with $$\text{Fe}^{2+}$$/Fe and $$\text{Cd}^{2+}$$/Cd at $$25^\circ\text{C}$$ with initial concentrations of $$[\text{Fe}^{2+}]$$ = 0.800 M and $$[\text{Cd}^{2+}]$$ = 0.250 M. The EMF of the cell when $$[\text{Cd}^{2+}]$$ becomes 0.100 M is

A

0.013 V

B

0.011 V

C

0.051 V

D

0.022 V

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NSEC 2019 24th Nov - Question 28

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The alkene ligand ($$\pi\text{-C}_2\text{R}_4$$) is both a sigma donor and a pi acceptor, similar to the CO ligand in metal carbonyls, and exhibits synergic bonding with metals. Correct order of C-C bond length in $$\text{K}[\text{PtCl}_3(\pi\text{-C}_2\text{R}_4)]$$ complexes in which R = H, F or CN is

A

H > F > CN

B

H > CN > F

C

CN > F > H

D

F > H > CN

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NSEC 2019 24th Nov - Question 29

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The correct order of CFSE among $$[\text{Zn(NH}_3)_4]^{2+}$$, $$[\text{Co(NH}_3)_6]^{2+}$$ and $$[\text{Co(NH}_3)_6]^{3+}$$ is

A

$$[\text{Co(NH}_3)_6]^{3+} > [\text{Co(NH}_3)_6]^{2+} > [\text{Zn(NH}_3)_4]^{2+}$$

B

$$[\text{Zn(NH}_3)_4]^{2+} > [\text{Co(NH}_3)_6]^{2+} > [\text{Co(NH}_3)_6]^{3+}$$

C

$$[\text{Co(NH}_3)_6]^{3+} > [\text{Zn(NH}_3)_4]^{2+} > [\text{Co(NH}_3)_6]^{2+}$$

D

$$[\text{Co(NH}_3)_6]^{2+} > [\text{Co(NH}_3)_6]^{3+} > [\text{Zn(NH}_3)_4]^{2+}$$

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NSEC 2019 24th Nov - Question 30

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The number of asymmetric carbon atoms in strychnine, whose structure given below is

A

5

B

4

C

6

D

7

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NSEC 2019 24th Nov - Question 31

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When acid X is heated to $$230^\circ\text{C}$$, along with $$\text{CO}_2$$ and $$\text{H}_2\text{O}$$, a compound Y is formed. If X is $$\text{HOOC(CH}_2)_2\text{CH(COOH)}_2$$ the structure of Y is

A

B

C

D

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NSEC 2019 24th Nov - Question 32

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Number of products formed (ignoring stereoisomerism) in the monochlorination of ethylcyclohexane is

A

6

B

8

C

5

D

4

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NSEC 2019 24th Nov - Question 33

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Molten NaCl is electrolysed for 35 minutes with a current of 3.50 A at $$40^\circ\text{C}$$ and 1 bar pressure. Volume of chlorine gas evolved in this electrolysis is

A

0.016 L

B

0.98 L

C

9.8 L

D

1.96 L

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NSEC 2019 24th Nov - Question 34

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A balance having a precision of 0.001 g was used to measure a mass of a sample of about 15 g. The number of significant figures to be reported in this measurement is

A

2

B

3

C

5

D

1

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NSEC 2019 24th Nov - Question 35

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Which of the following pairs of compounds can be stable while retaining the identity of each compound in the pair over a period of time? I. $$\text{FeCl}_3$$ and $$\text{SnCl}_2$$. II. $$\text{HgCl}_2$$ and $$\text{SnCl}_2$$. III. $$\text{FeCl}_2$$ and $$\text{SnCl}_2$$. IV. $$\text{FeCl}_3$$ and KI.

A

I only

B

I and III

C

III only

D

II and IV

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NSEC 2019 24th Nov - Question 36

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Which of the following is correct about the isoelectronic species, $$\text{Li}^+$$ and $$\text{H}^-$$?
I. $$\text{H}^-$$ is larger in size than $$\text{Li}^+$$.
II. $$\text{Li}^+$$ is a better reducing agent than $$\text{H}^-$$.
III. It requires more energy to remove an electron from $$\text{H}^-$$ than from $$\text{Li}^+$$.
IV. The chemical properties of the two ions are the same.

A

I only

B

II and III

C

I, II and IV

D

I and II

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NSEC 2019 24th Nov - Question 37

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The major product P formed in the following sequence of reactions is

A

B

C

D

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NSEC 2019 24th Nov - Question 38

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Sodium lauryl sulphate (SLS) is a surface active agent, which is adsorbed on water surface. The number of molecules of SLS that can be adsorbed on the surface of a spherical water droplet of diameter 3.5 mm is (effective area of one molecule of SLS is $$4.18\ \text{nm}^2$$)

A

$$9.20 \times 10^{12}$$

B

$$9.20 \times 10^{18}$$

C

$$1.15 \times 10^{12}$$

D

$$3.68 \times 10^{13}$$

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NSEC 2019 24th Nov - Question 39

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The reaction $$xX(g) \rightleftharpoons yY(g) + zZ(g)$$ was carried out at a certain temperature with an initial pressure of X of 30 bar. Initially Y and Z were not present. If the equilibrium partial pressures of X, Y and Z are 20, 5 and 10 bar respectively, $$x \colon y \colon z$$ is

A

$$4 \colon 1 \colon 2$$

B

$$2 \colon 1 \colon 2$$

C

$$1 \colon 2 \colon 1$$

D

$$1 \colon 1 \colon 2$$

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NSEC 2019 24th Nov - Question 40

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The unit of Planck's constant, h, is the same as that of

A

angular momentum

B

energy

C

wavelength

D

frequency

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NSEC 2019 24th Nov - Question 41

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A commercial sample of oleum ($$\text{H}_2\text{S}_2\text{O}_7$$) labeled as 106.5 % oleum contains 6.5 g of water. The percentage of free $$\text{SO}_3$$ in this oleum sample is

A

2.88

B

28.8

C

0.029

D

0.28

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NSEC 2019 24th Nov - Question 42

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Among the following, the complex ion or ions that will have a magnetic moment of 2.82 B.M. is or are I. $$[\text{Ni(CO)}_4]$$. II. $$[\text{NiCl}_4]^{2-}$$. III. $$[\text{Ni(H}_2\text{O})_6]^{2+}$$. IV. $$[\text{Ni(CN)}_4]^{2-}$$.

A

I and IV

B

II only

C

II and III

D

II, III and IV

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NSEC 2019 24th Nov - Question 43

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A suboxide of carbon, $$\text{C}_3\text{O}_2$$, has a linear structure. Which of the following is correct about $$\text{C}_3\text{O}_2$$?
I. Oxidation state of all three C atoms is +2.
II. Oxidation state of the central C atom is zero.
III. The molecule contains 4 sigma and 4 pi bonds.
IV. Hybridization of the central carbon atom is $$sp^2$$.

A

I and IV

B

II and III

C

II and IV

D

III only

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NSEC 2019 24th Nov - Question 44

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Among the following, the compounds with highest and lowest boiling points respectively are

A

I and III

B

II and III

C

I and IV

D

II and V

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NSEC 2019 24th Nov - Question 45

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Saran wrap, a polymer used in food packaging is a copolymer of 1,1-dichloroethene and vinyl chloride. In the chain initiation step, 1,1-dichloroethene generates a free radical which reacts with vinyl chloride. Structure of Saran wrap is

A

B

C

D

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NSEC 2019 24th Nov - Question 46

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At $$25^\circ\text{C}$$ the $$K_a$$ values of $$\text{HPO}_4^{2-}$$ and $$\text{HSO}_3^-$$ are $$4.8 \times 10^{-13}$$ and $$6.3 \times 10^{-8}$$ respectively. Which of the following is correct?

A

$$\text{HPO}_4^{2-}$$ is a stronger acid than $$\text{HSO}_3^-$$ and $$\text{PO}_4^{3-}$$ is a weaker base than $$\text{SO}_3^{2-}$$

B

$$\text{HPO}_4^{2-}$$ is a weaker acid than $$\text{HSO}_3^-$$ and $$\text{PO}_4^{3-}$$ is a weaker base than $$\text{SO}_3^{2-}$$

C

$$\text{HPO}_4^{2-}$$ is a weaker acid than $$\text{HSO}_3^-$$ and $$\text{PO}_4^{3-}$$ is a stronger base than $$\text{SO}_3^{2-}$$

D

$$\text{HPO}_4^{2-}$$ is a stronger acid than $$\text{HSO}_3^-$$ and $$\text{PO}_4^{3-}$$ is a stronger base than $$\text{SO}_3^{2-}$$

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NSEC 2019 24th Nov - Question 47

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The change in internal energy for the reaction $$\text{H}_2(g) + \text{Br}_2(g) \rightarrow 2\text{HBr}(l)$$ when 2.0 moles each of $$\text{Br}_2(g)$$ and $$\text{H}_2(g)$$ react is, given that for $$\text{H}_2(g) + \text{Br}_2(g) \rightarrow 2\text{HBr}(g)$$ the enthalpy of reaction is $$-109$$ kJ and the enthalpy of vaporisation of HBr is 213 kJ $$\text{mol}^{-1}$$

A

$$-644$$ kJ

B

644 kJ

C

$$-322$$ kJ

D

$$-1070$$ kJ

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NSEC 2019 24th Nov - Question 48

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About sea water, which of the following statement or statements is or are correct?
I. Frozen sea water melts at a lower temperature than pure ice.
II. Boiling point of sea water increases as it evaporates.
III. Sea water boils at a lower temperature than fresh water.
IV. Density of sea water at STP is same as that of fresh water.

A

I only

B

I and II

C

I, II and III

D

III only

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NSEC 2019 24th Nov - Question 49

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Which of the following species has one lone pair of electrons on the central atom?

A

$$\text{ClF}_3$$

B

$$\text{I}_3^-$$

C

$$\text{I}_3^+$$

D

$$\text{SF}_4$$

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NSEC 2019 24th Nov - Question 50

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The alkene Y in the following reaction is

A

B

C

D

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NSEC 2019 24th Nov - Question 51

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The structure that represents the major intermediate formed in the bromination of toluene is

A

B

C

D

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NSEC 2019 24th Nov - Question 52

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The major product P formed in the following reaction is, where the asterisk denotes radioactive carbon

A

B

C

D

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NSEC 2019 24th Nov - Question 53

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If the standard electrode potentials of $$\text{Fe}^{3+}$$/Fe and $$\text{Fe}^{2+}$$/Fe are $$-0.04$$ V and $$-0.44$$ V respectively, then that of $$\text{Fe}^{3+}$$/$$\text{Fe}^{2+}$$ is

A

0.76 V

B

$$-0.76$$ V

C

0.40 V

D

$$-0.40$$ V

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NSEC 2019 24th Nov - Question 54

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Given below is the data for the reaction $$2\text{NO}(g) \rightleftharpoons \text{N}_2(g) + \text{O}_2(g)$$,where $$k_f$$ and $$k_b$$ are the rate constants of the forword and reverse reaction respectively,  The reaction is

A

exothermic and $$K_{eq}$$ at 1400 K is $$3.79 \times 10^{-6}$$

B

endothermic and $$K_{eq}$$ at 1400 K is $$2.63 \times 10^{-5}$$

C

exothermic and $$K_{eq}$$ at 1400 K is $$1.8 \times 10^5$$

D

endothermic and $$K_{eq}$$ at 1500 K is $$9.28 \times 10^{-4}$$

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NSEC 2019 24th Nov - Question 55

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The crystal defect indicated in the diagram below is

A

Frenkel defect

B

Schottky defect

C

Frenkel and Schottky defects

D

Interstitial defect

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NSEC 2019 24th Nov - Question 56

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In solid state, $$\text{PCl}_5$$ exists as $$[\text{PCl}_4]^+[\text{PCl}_6]^-$$. The hybridization of P atoms in this solid is or are

A

$$sp^3d$$ with $$d = d_{x^2-y^2}$$

B

$$sp^3d$$ with $$d = d_{z^2}$$

C

$$sp^3$$ and $$sp^3d^2$$ with $$d = d_{x^2-y^2}$$ and $$d_{z^2}$$

D

$$sp^3d$$ and $$dsp^3$$ with $$d = d_{z^2}$$

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NSEC 2019 24th Nov - Question 57

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Which of the following compounds have chiral carbon atom or atoms? I is cyclopent-2-en-1-ol, II is cyclopent-3-en-1-ol, III is but-3-en-2-ol, IV is cyclohex-2-en-1-ol and V is 3-chlorobutan-2-ol.

A

I and II

B

I, III, IV and V

C

II, IV and V

D

II, III and IV

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NSEC 2019 24th Nov - Question 58

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Lipoic acid with the following structure is a growth factor required by many organisms. Percentages of S and O in lipoic acid respectively are (atomic masses of S and O are 32.065 g $$\text{mol}^{-1}$$ and 15.999 g $$\text{mol}^{-1}$$ respectively)

A

33.03, 16.48

B

31.11, 18.24

C

31.11, 15.52

D

31.42, 15.68

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NSEC 2019 24th Nov - Question 59

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Among the halides $$\text{NCl}_3$$ (I), $$\text{PCl}_3$$ (II) and $$\text{AsCl}_3$$ (III), more than one type of acid in aqueous solution is formed with

A

I, II and III

B

II only

C

I and II

D

II and III

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NSEC 2019 24th Nov - Question 60

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A helium cylinder in which the volume of gas is 2.24 L at STP (1 atm, 273 K) developed a leak and when the leak was plugged the pressure in the cylinder was seen to have dropped to 550 mm of Hg. The number of moles of He gas that had escaped due to this leak is

A

0.028

B

0.072

C

0.972

D

0.099

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NSEC 2019 24th Nov - Question 61

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The anhydride of $$\text{HNO}_3$$ is

A

NO

B

$$\text{NO}_2$$

C

$$\text{N}_2\text{O}$$

D

$$\text{N}_2\text{O}_5$$

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NSEC 2019 24th Nov - Question 62

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An excess of aqueous ammonia is added to three different flasks $$\text{F}_1$$, $$\text{F}_2$$ and $$\text{F}_3$$ containing aqueous solutions of $$\text{CuSO}_4$$, $$\text{Fe}_2(\text{SO}_4)_3$$ and $$\text{NiSO}_4$$ respectively. Which of the following is correct about this addition?
I. A precipitate will be formed in all three flasks.
II. Ammonia acts as a base as well as a ligand exchange reagent in $$\text{F}_1$$ and $$\text{F}_3$$.
III. A soluble complex of $$\text{NH}_3$$ and the metal ion is formed in $$\text{F}_1$$ and $$\text{F}_3$$.
IV. A precipitate will be formed only in $$\text{F}_2$$.

A

I only

B

IV only

C

II and IV

D

II, III and IV

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NSEC 2019 24th Nov - Question 63

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The mass (g) of NaCl that has to be dissolved to reduce the vapour pressure of 100 g of water by 10 % (Molar mass of NaCl is 58.5 g $$\text{mol}^{-1}$$) is

A

36.11 g

B

17.54 g

C

81.25 g

D

3.61 g

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NSEC 2019 24th Nov - Question 64

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The reagent or reagents that can be used to separate norethindrone and novestrol from their mixture is or are

A

III

B

I and IV

C

I, II and III

D

II

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NSEC 2019 24th Nov - Question 65

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Which of the following is or are electrophilic aromatic substitution reaction or reactions? 

A

II, III and IV

B

II and III

C

I, II and III

D

II only

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NSEC 2019 24th Nov - Question 66

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All four types of carbon (primary, secondary, tertiary and quaternary) are present in, 

A

I, II and III

B

II, III and IV

C

I, II and IV

D

II and III

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NSEC 2019 24th Nov - Question 67

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The normal boiling point and enthalpy of vaporisation of a liquid X are 400 K and 40 kJ $$\text{mol}^{-1}$$ respectively. Assuming the enthalpy of vaporisation to be constant, which of the following is correct?
I. The entropy of vaporisation is greater than $$100\ \text{J K}^{-1}\text{mol}^{-1}$$ at 400 K and 0.5 atm.
II. It is less than $$100\ \text{J K}^{-1}\text{mol}^{-1}$$ at 400 K and 1 atm.
III. It is less than $$100\ \text{J K}^{-1}\text{mol}^{-1}$$ at 400 K and 2 atm.
IV. It equals $$100\ \text{kJ K}^{-1}\text{mol}^{-1}$$ at 400 K and 1 atm.

A

II and IV

B

II only

C

I and III

D

I, III and IV

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NSEC 2019 24th Nov - Question 68

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About the energy level diagram given below, which of the following statement or statements is or are correct?

I. The reaction is of two steps and R is an intermediate.
II. The reaction is exothermic and step 2 is rate determining.
III. Q is an intermediate and R is the transition state for the reaction M to Q.
IV. P is the transition state for the reaction Q to N.

A

III and IV

B

I, III and IV

C

I, II and IV

D

III only

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NSEC 2019 24th Nov - Question 69

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Mercury is highly hazardous and hence its concentration is expressed in the units of ppb (micrograms of Hg present in 1 L of water). Permissible level of Hg in drinking water is 0.0335 ppb. Which of the following is an alternate representation of this concentration?

A

$$3.35 \times 10^{-2}\ \text{mg dm}^{-3}$$

B

$$3.35 \times 10^{-5}\ \text{mg dm}^{-3}$$

C

$$3.35 \times 10^{-5}\ \text{mg m}^{-3}$$

D

$$3.35 \times 10^{-4}\ \text{g L}^{-1}$$

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NSEC 2019 24th Nov - Question 70

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Which of the following is correct?
I. Sodium (Na) is present as metal in nature.
II. $$\text{Na}_2\text{O}_2$$ is paramagnetic.
III. $$\text{NaO}_2$$ is paramagnetic.
IV. Na reacts with $$\text{N}_2$$ to form $$\text{Na}_3\text{N}$$.

A

III only

B

II and IV

C

I, III and IV

D

II, III and IV

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NSEC 2019 24th Nov - Question 71

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The F-X-F bond angle is the smallest in (X is the central atom)

A

$$\text{CF}_4$$

B

$$\text{NF}_3$$

C

$$\text{OF}_2$$

D

$$\text{XeF}_5^-$$

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NSEC 2019 24th Nov - Question 72

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The correct sequence of reactions which will yield 4-nitrobenzoic acid from benzene is

A

$$\text{CH}_3\text{Cl}$$; $$\text{HNO}_3$$ with $$\text{H}_2\text{SO}_4$$; $$\text{KMnO}_4$$ with $$\text{OH}^-$$

B

$$\text{HNO}_3$$ with $$\text{H}_2\text{SO}_4$$; $$\text{CH}_3\text{Cl}$$ with $$\text{AlCl}_3$$; $$\text{KMnO}_4$$ with $$\text{OH}^-$$

C

$$\text{CH}_3\text{Cl}$$ with $$\text{AlCl}_3$$; $$\text{KMnO}_4$$ with $$\text{OH}^-$$; $$\text{HNO}_3$$ with $$\text{H}_2\text{SO}_4$$

D

$$\text{CH}_3\text{Cl}$$ with $$\text{AlCl}_3$$; $$\text{HNO}_3$$ with $$\text{H}_2\text{SO}_4$$; $$\text{KMnO}_4$$ with $$\text{OH}^-$$

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NSEC 2019 24th Nov - Question 73

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Two isomeric hydrocarbons X and Y ($$\text{C}_4\text{H}_6$$), give the same product ($$\text{C}_4\text{H}_8\text{O}$$) on catalytic hydration with dilute acid. However, they form different products but with same molecular formula ($$\text{C}_4\text{H}_6\text{Br}_4$$) when treated with excess bromine. X and Y are

A

B

C

D

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NSEC 2019 24th Nov - Question 74

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Morphine, a pain killer is basic with the molecular formula $$\text{C}_{17}\text{H}_{19}\text{NO}_3$$. The conjugate acid of morphine is

A

$$\text{C}_{17}\text{H}_{19}\text{NO}_3^+$$

B

$$\text{C}_{17}\text{H}_{18}\text{NO}_3$$

C

$$\text{C}_{17}\text{H}_{19}\text{NO}_3^-$$

D

$$\text{C}_{17}\text{H}_{20}\text{NO}_3^+$$

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NSEC 2019 24th Nov - Question 75

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The correct IUPAC name of the compound, $$[\text{Pt(py)}_4][\text{Pt(Br)}_4]$$ is

A

tetrapyridineplatinum(II) tetrabromidoplatinate(II)

B

tetrabromidoplatinum(IV) tetrapyridineplatinate(II)

C

tetrabromidoplatinate(II) tetrapyridineplatinum(II)

D

tetrapyridineplatinum(IV) tetrabromidoplatinate(IV)

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NSEC 2019 24th Nov - Question 76

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Which atom or atoms will have a $$\delta^{+}$$ charge in the following molecule?

A

I and III

B

II only

C

II and III

D

II and IV

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NSEC 2019 24th Nov - Question 77

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The most acidic hydrogen in the following molecule is

A

I

B

II

C

III

D

IV

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NSEC 2019 24th Nov - Question 78

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In which of the following species is the octet rule NOT obeyed? I. $$\text{I}_3^-$$. II. $$\text{N}_2\text{O}$$. III. $$\text{OF}_2$$. IV. $$\text{NO}^+$$.

A

I and IV

B

II and III

C

I only

D

IV only

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NSEC 2019 24th Nov - Question 79

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The volume of one drop of aqueous solution from an eyedropper is approximately 0.05 mL. One such drop of 0.2 M HCl is added to 100 mL of distilled water. The pH of the resulting solution will be

A

4.0

B

7.0

C

3.0

D

5.5

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NSEC 2019 24th Nov - Question 80

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2.0 moles of an ideal gas expands isothermally at $$27^\circ\text{C}$$ and reversibly between pressures of 1 bar and 10 bar. The heaviest mass that can be lifted through a height of 10 m by the work of this expansion is

A

50.8 kg

B

50.8 g

C

117.1 kg

D

117.1 g

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