NSEC 2018 25th Nov Question Paper

NSEC 2018 25th Nov - Question 1

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Which of the energy values marked as I, II and III in the following diagram, will change by the addition of a suitable catalyst?

A

II only

B

I and II

C

II and III

D

III only

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NSEC 2018 25th Nov - Question 2

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The product 'X' in the following reaction is

A

a racemic mixture of ester

B

an optically inactive ester

C

an optically active ester

D

a meso ester

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NSEC 2018 25th Nov - Question 3

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At 298 K, change in internal energy for the complete combustion of fullerene, $$\text{C}_{60}(s)$$, an allotrope of carbon, and the enthalpy of formation of $$\text{CO}_2(g)$$ are $$-25970\ \text{kJ mol}^{-1}$$ and $$-393\ \text{kJ mol}^{-1}$$ respectively. The enthalpy of formation of $$\text{C}_{60}(s)$$ at 298 K is

A

$$-2390\ \text{kJ}$$

B

$$4.95 \times 10^4\ \text{kJ}$$

C

$$2.60 \times 10^4\ \text{kJ}$$

D

$$2390\ \text{kJ}$$

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NSEC 2018 25th Nov - Question 4

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Which of the following is not paramagnetic?

A

$$\text{S}^{2-}$$

B

$$\text{N}_2^-$$

C

$$\text{O}_2^-$$

D

NO

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NSEC 2018 25th Nov - Question 5

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Solubility product of AgCl is $$1.8 \times 10^{-10}$$. The minimum volume (in L) of water required to dissolve 1 mg of AgCl is close to

A

0.5

B

7.5

C

50

D

0.75

View Solution

NSEC 2018 25th Nov - Question 6

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The complex $$[\text{M(en)(Br)}_2(\text{Cl})_2]$$ has two optical isomers. Their configurations can be represented as

A

B

C

D

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NSEC 2018 25th Nov - Question 7

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A sample of water from a river was analyzed for the presence of metal ions and the observations were recorded as given below

The water sample is likely to contain

A

$$\text{Ba}^{2+}$$

B

$$\text{Cu}^{2+}$$

C

$$\text{Li}^+$$

D

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

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NSEC 2018 25th Nov - Question 8

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The lattice enthalpy and enthalpy of solution in water for solid NaCl are $$753\ \text{kJ mol}^{-1}$$ and $$5\ \text{kJ mol}^{-1}$$ respectively. If the solution enthalpies of $$\text{Na}^+$$ and $$\text{Cl}^-$$ are in the ratio $$6 \colon 5$$, the enthalpy of hydration of $$\text{Na}^+$$ ion is

A

$$408\ \text{kJ mol}^{-1}$$

B

$$-412\ \text{kJ mol}^{-1}$$

C

$$-408\ \text{kJ mol}^{-1}$$

D

$$-412 \text{ kJ mol}^{-1}$$

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NSEC 2018 25th Nov - Question 9

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The gaseous product obtained on reaction of $$\text{BF}_3$$ with LiH is

A

HF

B

$$\text{H}_2$$

C

$$\text{B}_2\text{H}_6$$

D

$$\text{F}_2$$

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NSEC 2018 25th Nov - Question 10

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The equilibrium constant K for the reversible reaction $$A \rightleftharpoons B$$ is $$2 \times 10^3$$ at 350 K. The rate constants of the forward reaction in the presence and absence of a suitable catalyst at the same temperature are $$5 \times 10^4\ \text{s}^{-1}$$ and $$4 \times 10^{-6}\ \text{s}^{-1}$$ respectively. The rate constant of the reverse reaction in the absence of the catalyst is

A

$$2 \times 10^{-3}\ \text{s}^{-1}$$

B

$$2.5 \times 10^{-1}\ \text{s}^{-1}$$

C

$$1.6 \times 10^{-7}\ \text{s}^{-1}$$

D

$$1.25 \times 10^{-2}\ \text{s}^{-1}$$

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NSEC 2018 25th Nov - Question 11

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The number of stereoisomers possible for the following compound

A

4

B

2

C

16

D

32

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NSEC 2018 25th Nov - Question 12

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An adsorption isotherm equation proposed by Langmuir is of the form $$V = \frac{V_0 bP}{1 + bP}$$ where V is the volume of gas adsorbed at pressure P. For a given adsorbate or adsorbent system, $$V_0$$ and b are constants. The dependence of V on P can be depicted as

A

B

C

D

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NSEC 2018 25th Nov - Question 13

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For the reaction $$4\text{NO}_2(g) + \text{O}_2(g) \to 2\text{N}_2\text{O}_5(g)$$, $$\Delta H_{reaction} = -112\ \text{kJ}$$. If the $$\text{N}_2\text{O}_5$$ is assumed to be formed in the reaction as a solid, $$\Delta H_{reaction}$$ will be (the enthalpy of sublimation of $$\text{N}_2\text{O}_5$$ is $$54\ \text{kJ mol}^{-1}$$)

A

$$-220\ \text{kJ}$$

B

$$-4\ \text{kJ}$$

C

$$-166\ \text{kJ}$$

D

$$-332\ \text{kJ}$$

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NSEC 2018 25th Nov - Question 14

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Urea, $$\text{CO(NH}_2)_2$$, decomposes at $$90^\circ\text{C}$$ as $$\text{CO(NH}_2)_2(aq) \to \text{NH}_4^+(aq) + \text{OCN}^-(aq)$$. Experimental data obtained for the reaction is given in the following plot

From the graph it can be inferred that

A

Average rate of the reaction is the same for successive time intervals of 10 h

B

unit of rate constant of the reaction is $$\text{h}^{-1}$$

C

rate constant of the reaction is the lowest at 30 h

D

the reaction is of zero order

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NSEC 2018 25th Nov - Question 15

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If for an aqueous solution of a weak acid, $$pH = pK_a + 2$$ at $$25^\circ\text{C}$$, the approximate fraction of the acid in the dissociated form is

A

1.1%

B

0.99%

C

99.0%

D

9.9%

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NSEC 2018 25th Nov - Question 16

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2.0 L of $$\text{N}_2$$ gas kept at $$25^\circ\text{C}$$ and 5 atm pressure were expanded isothermally against a constant pressure of 1 atm until the pressure of the gas reaches 1 atm. Assuming ideal behaviour, work of expansion in this process (in J) is close to

A

810 J

B

194 kJ

C

$$-810\ \text{kJ}$$

D

3390 kJ

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NSEC 2018 25th Nov - Question 17

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The compound which would undergo a reaction with ammonia by $$S_N1$$ mechanism is

A

B

C

D

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NSEC 2018 25th Nov - Question 18

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The daily energy requirement of a teenager is 7800 kJ. As calculated from the data given in the table below, the amount of glucose he has to consume (g) per day assuming that the entire energy he requires comes from the combustion of glucose is

A

262

B

500

C

131

D

250

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NSEC 2018 25th Nov - Question 19

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The pressure inside two gas cylinders of volume $$25\ \text{m}^3$$ and $$50\ \text{m}^3$$ are 10 kPa and 20 kPa respectively. The cylinders are kept at the same temperature and separated by a valve. What is the pressure in the combined system when the valve is opened?

A

30 kPa

B

15 kPa

C

16.7 kPa

D

2.5 kPa

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NSEC 2018 25th Nov - Question 20

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Aluminium and copper are extracted from their oxide and sulphide ores respectively. 

Which of the following is correct?

I. Copper is extracted by the auto reduction of copper oxide by copper sulphide. 

II. Aluminium cannot be obtained by chemical reduction due to its strong affinity for oxygen. 

III. In electrometallurgy of Al, graphite is used as cathode to avoid reoxidation of Al into $$\text{Al}_2\text{O}_3$$ by preventing formation of $$\text{O}_2$$. 

IV. Sulphide ores of copper are difficult to be reduced than the oxide ores

A

I, II, IV

B

II and III

C

Both II and III

D

II and IV

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NSEC 2018 25th Nov - Question 21

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Which of the following graphs describes the relationship between $$[\text{H}_3\text{O}^+]$$ and $$[\text{OH}^-]$$ in an aqueous solution at a constant temperature?

A

B

C

D

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NSEC 2018 25th Nov - Question 22

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From the given standard electrode potentials 

$$\text{Sn}^{4+}(aq) + 2e^- \to \text{Sn}^{2+}(aq)$$ $$E^0 = 0.15\ \text{V}$$ and $$\text{Br}_2(l) + 2e^- \to 2\text{Br}^-(aq)$$ with $$E^0 = 1.07\ \text{V}$$, the approximate free energy change for the process $$2\text{Br}^-(aq) + \text{Sn}^{4+}(aq) \to \text{Br}_2(l) + \text{Sn}^{2+}(aq)$$ is

A

177.6 kJ

B

355 kJ

C

$$-177.6\ \text{kJ}$$

D

$$-355\ \text{kJ}$$

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NSEC 2018 25th Nov - Question 23

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Number of moles of $$\text{KClO}_3$$ that have to be heated to produce 1.0 L of $$\text{O}_2(g)$$ at STP can be expressed as

A

$$\frac{1}{3}\left(\frac{1}{22.4}\right)$$

B

$$\frac{1}{2}\left(\frac{1}{22.4}\right)$$

C

$$\frac{2}{3}\left(\frac{1}{22.4}\right)$$

D

$$\frac{3}{2}(22.4)$$

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NSEC 2018 25th Nov - Question 24

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The sequence of reagents required for the following conversion is

A

(i) $$\text{B}_2\text{H}_6/\text{H}_2\text{O}_2/\text{OH}^-$$ (ii) Na (iii) $$\text{C}_2\text{H}_5\text{I}$$

B

(i) HCl (ii) $$\text{C}_2\text{H}_5\text{ONa}$$

C

(i) $$\text{H}_3\text{O}^+$$ (ii) Na (iii) $$\text{C}_2\text{H}_5\text{OH}$$

D

(i) $$\text{H}_3\text{O}^+$$ (ii) Na (iii) $$\text{C}_2\text{H}_5\text{Cl}$$

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NSEC 2018 25th Nov - Question 25

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Among the following, number of oxygen atoms present is the maximum in

A

1.0 g of $$\text{O}_2$$ molecules

B

4.0 g of O atoms

C

1.0 g of $$\text{O}_3$$

D

1.7 g of $$\text{H}_2\text{O}$$

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NSEC 2018 25th Nov - Question 26

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Which of the following elements will exhibit photoelectric effect with light of the longest wavelength?

A

K

B

Rb

C

Mg

D

Ca

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NSEC 2018 25th Nov - Question 27

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Compound 'X' in the following reaction is

A

B

C

D

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NSEC 2018 25th Nov - Question 28

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The standard molar entropies of $$\text{H}_2(g)$$, $$\text{N}_2(g)$$ and $$\text{NH}_3(g)$$ are 130, 190 and $$193\ \text{J mol}^{-1}\text{K}^{-1}$$ respectively. For the reaction $$\frac{1}{2}\text{N}_2(g) + \frac{3}{2}\text{H}_2(g) \rightleftharpoons \text{NH}_3(g)$$ with $$\Delta H_{reaction} = -45\ \text{kJ}$$ to be in equilibrium, the temperature must be equal to

A

464 K

B

928 K

C

737 K

D

354 K

View Solution

NSEC 2018 25th Nov - Question 29

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Density of $$\text{CO}_2$$ gas at $$0^\circ\text{C}$$ and 2.00 atm pressure can be expressed as

A

$$2\ \text{g m}^{-3}$$

B

$$4\ \text{g m}^{-3}$$

C

$$4 \times 10^3\ \text{kg m}^{-3}$$

D

$$8\ \text{g L}^{-1}$$

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NSEC 2018 25th Nov - Question 30

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The maximum number of moles of $$\text{CH}_3\text{I}$$ consumed by one mole of crixivan, a drug used against AIDS is

A

2

B

3

C

5

D

7

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NSEC 2018 25th Nov - Question 31

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Concentration of $$\text{K}^+$$ ions inside a biological cell was found to be 25 times higher than that outside. The magnitude of the potential difference between the two sides of the cell is close to (2.303 RT/F can be taken as 59 mV; difference in concentrations of other ions can be taken as negligible.)

A

4.2 mV

B

195 mV

C

82 mV

D

$$-82\ \text{mV}$$

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NSEC 2018 25th Nov - Question 32

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The standard redox potential for the reaction $$2\text{H}_2\text{O} \to \text{O}_2 + 4\text{H}^+ + 4e^-$$ is $$-1.23\ \text{V}$$. If the same reaction is carried out at $$25^\circ\text{C}$$ and at pH 7, the potential will be

A

$$-0.82\ \text{V}$$

B

$$-3.28\ \text{V}$$

C

0.82 V

D

$$-1.18\ \text{V}$$

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NSEC 2018 25th Nov - Question 33

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The order of $$pK_a$$ values of the following acids is

A

IV > I > III > II

B

III > IV > I > II

C

II > I > III > IV

D

II > III > I > IV

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NSEC 2018 25th Nov - Question 34

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If the radius of the hydrogen atom is 53 pm, the radius of the $$\text{He}^+$$ ion is close to

A

75 pm

B

38 pm

C

106 pm

D

27 pm

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NSEC 2018 25th Nov - Question 35

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A substance X was heated at constant pressure and the temperature observed at various times of heating was plotted as given below

Which of the following is or are correct?

I. Melting point of X is $$-5^\circ\text{C}$$. 

II. Solid and liquid forms of X coexist in the region b. 

III. Boiling point of X is $$55^\circ\text{C}$$.

IV. Solid and liquid forms of X coexist in the region d

A

I and IV

B

II and III

C

III only

D

I, II and III

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NSEC 2018 25th Nov - Question 36

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The major product of the following reaction is

A

B

C

D

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NSEC 2018 25th Nov - Question 37

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In which of the following, all the bond lengths are not the same? I. $$\text{IF}_4^+$$ II. $$\text{BF}_4^-$$ III. $$\text{SF}_4$$ IV. $$\text{TeCl}_4$$

A

I, II, IV

B

II, III, IV

C

I, III, IV

D

I, II, III

View Solution

NSEC 2018 25th Nov - Question 38

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Among the following, the reaction or reactions that can be classified as oxidation reduction is or are 

I. $$\text{Cr}_2\text{O}_7^{2-}(aq) + 2\text{OH}^-(aq) \to 2\text{CrO}_4^{2-} + \text{H}_2\text{O}(l)$$

II. $$\text{SiCl}_4(l) + 2\text{Mg}(s) \to 2\text{MgCl}_2(l) + \text{Si}(s)$$ 

III. $$6\text{Cl}_2(l) + 12\text{KOH}(l) \to 2\text{KClO}_3(s) + 10\text{KCl} + 6\text{H}_2\text{O}(l)$$

IV. $$2\text{H}_2\text{O}_2 \to 2\text{H}_2\text{O}(l) + \text{O}_2(g)$$

A

I and IV

B

I, II and III

C

II, III and IV

D

IV only

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NSEC 2018 25th Nov - Question 39

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Among the following pairs, the one in which both the compounds as pure liquids can show significant auto ionization is

A

$$\text{H}_2\text{O}$$ and $$\text{H}_2\text{S}$$

B

$$\text{BrF}_3$$ and $$\text{ICl}_3$$

C

$$\text{PF}_5$$ and $$\text{PCl}_5$$

D

HF and HCl

View Solution

NSEC 2018 25th Nov - Question 40

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The number of quaternary and chiral carbon atoms present in elatol, isolated from an algae are respectively

A

2, 3

B

4, 2

C

3, 2

D

1, 3

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NSEC 2018 25th Nov - Question 41

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Compounds X ($$pK_a$$ about 15) and Y ($$pK_a$$ about 10), both produce $$\text{H}_2$$ on treatment with sodium metal and both yield a mixture of isomers on mononitration. X and Y respectively are

A

IV, I

B

III, II

C

III, I

D

I, III

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NSEC 2018 25th Nov - Question 42

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A crystal of KCl containing a small amount of $$\text{CaCl}_2$$ will have

A

vacant $$\text{Cl}^-$$ sites

B

vacant $$\text{K}^+$$ sites and a higher density as compared to pure KCl

C

vacant $$\text{K}^+$$ sites and a lower density as compared to pure KCl

D

$$\text{K}^+$$ ions in the interstitial sites

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NSEC 2018 25th Nov - Question 43

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In the following reaction, the values of a, b and c, respectively are 

$$a\,\text{F}_2(g) + b\,\text{OH}^-(aq) \to c\,\text{F}^-(aq) + d\,\text{OF}_2(g) + e\,\text{H}_2\text{O}(l)$$

A

3, 2, 4

B

3, 4, 2

C

2, 2, 4

D

2, 2, 2

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NSEC 2018 25th Nov - Question 44

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The monosaccharide present in the following disaccharide is

A

B

C

D

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NSEC 2018 25th Nov - Question 45

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The IUPAC name of the complex $$[\text{Pt(en)(NH}_3)(\text{Cl})_2(\text{ONO})][\text{Ag(CN)}_2]$$ is

A

monoamminedichlorido(ethane-1,2-diammine)nitritoplatinum(IV) dicyanoargentate(I)

B

monoaminebischlorido(ethane-1,2-diamine)nitroplatinate(IV) dicyanosilver(I)

C

monoaminebischlorido(ethane-1,2-diammine)nitritoplatinate(IV) dicyanoargentate(I)

D

monoamminedichlorido(ethane-1,2-diamine)nitritoplatinum(IV) dicyanoargentate(I)

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NSEC 2018 25th Nov - Question 46

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The correct order of basicity of the following species is

A

III < IV < II < I

B

III < I < II < IV

C

III < II < I < IV

D

IV < I < II < III

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NSEC 2018 25th Nov - Question 47

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Which among the following is nonlinear?

A

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

B

$$\text{ClF}_2^-$$

C

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

D

$$\text{BrCl}_2^+$$

View Solution

NSEC 2018 25th Nov - Question 48

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The compound most likely to lose water on protonation is

A

B

C

D

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NSEC 2018 25th Nov - Question 49

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The Newman projection shown is the same as

A

I and IV

B

II and III

C

III and IV

D

I and II

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NSEC 2018 25th Nov - Question 50

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Which one of the following is not used as a monomer for the synthesis of a high molecular weight silicone polymer?

A

$$\text{MeSiCl}_3$$

B

$$\text{Me}_2\text{SiCl}_2$$

C

$$\text{Me}_3\text{SiCl}$$

D

$$\text{PhSiCl}_3$$

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NSEC 2018 25th Nov - Question 51

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In $$\text{YBa}_2\text{Cu}_3\text{O}_{7-x}$$, a superconducting oxide that got George Bednorz and Karl Muller the Nobel prize in 1986, Cu can exist in both $$+2$$ and $$+3$$ oxidation states and their proportion depends on the value of x. In $$\text{YBa}_2\text{Cu}_3\text{O}_{6.5}$$

A

0.5 moles of Cu are in $$+3$$ oxidation state

B

5% of Cu is in $$+3$$ oxidation state

C

All the Cu is in $$+3$$ oxidation state

D

All Cu is in $$+2$$ oxidation state

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NSEC 2018 25th Nov - Question 52

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Compound 'Y' (molar mass $$88.12\ \text{g mol}^{-1}$$) containing 54.52 % carbon, 9.17 % hydrogen and 36.31% oxygen gives a reddish-brown precipitate in Fehling's test. 'Y' is

A

B

C

D

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NSEC 2018 25th Nov - Question 53

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The IUPAC name of the following compound is

A

1-Bromo-4-chloro-3-ethenylbutane

B

4-Bromo-1-chloro-3-ethenylbutane

C

3-(Bromomethyl)-5-chloropent-1-ene

D

3-(Bromomethyl)-1-chloropent-4-ene

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NSEC 2018 25th Nov - Question 54

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The correct order of boiling points of the following compounds is

A

III < IV < II < I

B

I < III < IV < II

C

I < II < III < IV

D

IV < III < I < II

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NSEC 2018 25th Nov - Question 55

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Which of the following is a strong oxidising agent?

A

$$\text{AlCl}_3$$

B

$$\text{TlCl}_3$$

C

$$\text{NF}_3$$

D

$$\text{PCl}_3$$

View Solution

NSEC 2018 25th Nov - Question 56

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The molecule in which all atoms are not coplanar is

A

B

C

D

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NSEC 2018 25th Nov - Question 57

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The most stable radical among the following is

A

B

C

D

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NSEC 2018 25th Nov - Question 58

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During World War II, soldiers posted at high altitudes experienced crumbling of the tin buttons of their uniforms into a grey powder. This can be attributed to

A

oxidation of tin

B

interaction with nitrogen in the air at low pressure

C

change in the crystal structure of tin

D

reaction of tin with water vapour in the air

View Solution

NSEC 2018 25th Nov - Question 59

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The molecules that can exhibit tautomerism are

A

I, IV

B

II, III

C

III, IV

D

I, II

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NSEC 2018 25th Nov - Question 60

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A scientist attempts to replace a few carbon atoms in 1.0 g of diamond with boron atoms or nitrogen atoms in separate experiments. Which of the following is correct?

A

The resulting material with B doping will be an n-type semiconductor

B

The resulting material with B doping will be a p-type semiconductor

C

B doping is NOT possible as B cannot form multiple bonds

D

The resulting material with N doping will be a p-type semiconductor

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NSEC 2018 25th Nov - Question 61

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Compound 'P' that undergoes the sequence of reactions given below to give the product Q is

A

B

C

D

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NSEC 2018 25th Nov - Question 62

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The most stable Lewis structure of $$\text{N}_2\text{O}$$ is

A

B

C

D

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NSEC 2018 25th Nov - Question 63

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The major product 'X' formed in the following reaction is

A

B

C

D

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NSEC 2018 25th Nov - Question 64

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Which of the following accounts best for the fact that $$\text{F}^-$$ is smaller than $$\text{O}^{2-}$$?

A

$$\text{F}^-$$ has a larger nuclear mass than $$\text{O}^{2-}$$

B

$$\text{F}^-$$ has a larger nuclear charge than $$\text{O}^{2-}$$

C

$$\text{F}^-$$ is more polarizable than $$\text{O}^{2-}$$

D

F is more electronegative than O

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NSEC 2018 25th Nov - Question 65

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The correct sequence of reagents from those listed below for the following conversion is 

I. $$\text{NaNH}_2$$

II. $$\text{Br}_2$$ 

III. $$\text{H}_2$$ over Pd-C with quinoline 

IV. $$\text{H}_3\text{O}^+$$

A

IV - I - III

B

III - IV - I

C

II - I - III

D

I - II - III

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NSEC 2018 25th Nov - Question 66

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An orbital among the following that has two radial nodes and two angular nodes is

A

3d

B

4p

C

4f

D

5d

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NSEC 2018 25th Nov - Question 67

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The compound 'X' undergoing the following reaction is

A

B

C

D

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NSEC 2018 25th Nov - Question 68

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A dilute solution of an alkali metal in liquid ammonia is 

I. blue in colour

II. conducts electricity

III. paramagnetic 

IV. an oxidising agent

A

I and III

B

II and IV

C

I, II and III

D

I and III only

View Solution

NSEC 2018 25th Nov - Question 69

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The reactions from those given below that involve a carbocation intermediate are

A

i, ii and iii

B

i and ii

C

i and iii

D

ii and iii

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NSEC 2018 25th Nov - Question 70

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The C-O bond length is the shortest in

A

$$[\text{Cr(CO)}_6]$$

B

$$[\text{Mo(CO)}_6]$$

C

$$[\text{Mn(CO)}_6]^+$$

D

$$[\text{V(CO)}_6]^-$$

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NSEC 2018 25th Nov - Question 71

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The rate of the reaction between two reactants X and Y can be expressed as $$R = k[X]^2[Y]$$. In an experiment, the initial rate of the reaction was found to be $$R_1$$ when the initial concentrations of X and Y are $$[X_0]$$ and $$[Y_0]$$. Another experiment was performed in which $$[X_0]$$ was taken as $$\frac{1}{2}[X_0]$$. What should be $$[Y_0]$$ in this experiment to get the initial rate as $$0.5R_1$$?

A

$$4[Y_0]$$

B

$$\frac{1}{2}[Y_0]$$

C

$$2[Y_0]$$

D

$$[Y_0]$$

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NSEC 2018 25th Nov - Question 72

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Among the following, the compound that has the highest dipole moment is

A

$$\text{CH}_3\text{COOCH}_3$$

B

$$\text{CH}_3\text{CONH}_2$$

C

$$\text{CH}_3\text{COC}_2\text{H}_5$$

D

$$\text{CH}_3\text{COCl}$$

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NSEC 2018 25th Nov - Question 73

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A common method to clean acid spills is to use $$\text{Na}_2\text{CO}_3$$ (Molar mass 106 g). If 50.0 mL of 0.75 M HCl is spilt on a wooden surface, the amount of $$\text{Na}_2\text{CO}_3$$ required is

A

3.75 g

B

7.5 g

C

2.0 g

D

4.0 g

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NSEC 2018 25th Nov - Question 74

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The spin-only magnetic moments of $$[\text{Fe(NH}_3)_6]^{3+}$$ and $$[\text{FeF}_6]^{3-}$$ (in units of BM) respectively are

A

1.73 and 1.73

B

5.92 and 1.73

C

1.73 and 5.92

D

5.92 and 5.92

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NSEC 2018 25th Nov - Question 75

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The major product of the following reaction is

A

B

C

D

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NSEC 2018 25th Nov - Question 76

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The standard electrode potential of the Daniel cell is 1.1 V and the overall cell reaction can be represented as $$\text{Zn}(s) + \text{Cu}^{2+}(aq) \to \text{Zn}^{2+}(aq) + \text{Cu}(s)$$. Under which of the following conditions will the cell potential be higher than 1.1 V?

A

$$1.0\ \text{M}\ \text{Zn}^{2+}$$, $$1.0\ \text{M}\ \text{Cu}^{2+}$$

B

$$1.2\ \text{M}\ \text{Zn}^{2+}$$, $$1.2\ \text{M}\ \text{Cu}^{2+}$$

C

$$0.1\ \text{M}\ \text{Zn}^{2+}$$, $$1.0\ \text{M}\ \text{Cu}^{2+}$$

D

$$1.0\ \text{M}\ \text{Zn}^{2+}$$, $$0.01\ \text{M}\ \text{Cu}^{2+}$$

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NSEC 2018 25th Nov - Question 77

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Penicillamine is used in the treatment of arthritis. One molecule of penicillamine contains a single sulphur atom and the weight percentage of sulphur in penicillamine is 21.49%. Molecular weight of penicillamine in $$\text{g mol}^{-1}$$ is

A

85.40

B

68.76

C

125.2

D

149.2

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NSEC 2018 25th Nov - Question 78

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An ion exchange resin, $$\text{RH}_2$$, can replace $$\text{Ca}^{2+}$$ in hard water as $$\text{RH}_2 + \text{Ca}^{2+} \to \text{RCa}^{2+} + 2\text{H}^+$$. When a 1.0 L hard water sample was passed through the resin, all $$\text{H}^+$$ ions were replaced by $$\text{Ca}^{2+}$$ ions and the pH of eluted water was found to be 2.0. The hardness of water (as ppm of $$\text{Ca}^{2+}$$) in the sample of water treated is

A

50

B

100

C

125

D

200

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NSEC 2018 25th Nov - Question 79

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The analysis of three different binary oxides of bromine (Br) and oxygen (O) gives the following results

Which of the following statements is not correct? 

I. Compound Y is $$\text{Br}_2\text{O}_3$$ 

II. Compound Z is $$\text{Br}_2\text{O}_5$$

III. Compound Z is $$\text{Br}_2\text{O}_7$$ 

IV. Compound Y is $$\text{Br}_2\text{O}_5$$

A

I and III

B

II and IV

C

III and IV

D

I and II

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NSEC 2018 25th Nov - Question 80

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Which of the following statements is or are correct? 

I. Number of significant figures in 2345.100 is three 

II. 0.00787 rounded to two significant figures is written as $$0.787 \times 10^{-2}$$ 

III. 340 rounded to two significant figures is written as $$0.34 \times 10^3$$

IV. The number of significant figures in 0.020 is two

A

II and III

B

III and IV

C

I, II and IV

D

III only

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