PYQ 2016 - VedPrep

GATE Chemistry 2016
Previous Year Question Paper with Solution.

1. [CpMoCl₂]₂ obeys the 18 electron rule. The correct structure of this compound is (atomic number of Mo = 42)

(a)

(b)

(c)

(d)

Ans. (c)

Sol. According to 18 electron count of neutral atom method ;

Unit Contribution of electron

M–M bond (Mo–Mo) 2

Bridging halogen (Mo–Cl–Mo) 3

Mo 6

Cp 5

Hence, 2Mo atom

2 × 6 = 12 e^–

4μ₂–Cl 4 × 3 = 12 e^–

2Cp 2 × 5 = 10 e^–

One (Mo–Mo) bond 1 × 2 = 2 e^–

36 e^–

Hence, Per Mo 18 electron

Correct option is (c)

2. During oxygen transport by hemerythrin, oxygen is bound as

(a) O₂^– to one Fe(III) only

(b) HO₂^– to one Fe(III) only

(d) O₂^2– to two Fe(II)

Ans. (b)

Sol. During oxygen transport by hemerythrin, oxygen is bound as HO₂^– to one Fe(III) only

Correct option is (b)

3. Among the following, the most stable isotope to radioactive decay is

(a)

(b)

(c)

(d)

Ans. (a)

Sol. Lead (Pb) has four stable isotopes :

²⁰⁴Pb, ²⁰⁶Pb, ²⁰⁷Pb, ²⁰⁸Pb, ²⁰⁴Pb is entering a primordial nuclide and is not a radiogenic nucldie

Correct option is (a)

4. At pH 7.2 and 10 Torr oxygen partial pressure, the extent of O₂ binding is

(a) high for both haemoglobin and myoglobin

(b) high for haemoglobin and low for myoglobin

(d) low for both haemoglobin and myoglobin

Ans. (c)

Sol. At low pH and low pressure Hb has less oxygen binding tendency. While for Mb is more oxygen binding tendency.

Correct option is (c)

5. In the first row high-spin transition metal complexes [M(H₂O)₆]Cl₂ with d⁵ and d⁷ metal ions, the d-d transitions are

(a) spin-forbidden for both

(b) spin-allowed for both

(d) spin-allowed for d⁵ and spin-forbidden for d⁷

Ans. (c)

Sol. , high spin complex with d⁵ configuration

[M(H₂O)₆]Cl₂ with d⁷ configuration is spin allowed and with d⁵ spin forbidden.

Correct option is (c)

6. Among the given boranes and heteroboranes, the example which belongs to 'closo' type is

(a)

(b)

(d) B₆H₁₀

Ans. (c)

Sol. Hetero atom Replace with

C, Si, Ge, Sn BH

N, P, As BH₂

S, Se BH₃

(a) B₅H₈^– is derived from B₅H₅^4–, a nido speices

(b) [C₂B₉H₁₁]^2– is equivalent to B₁₁H₁₃^–2, derived from B₁₁H₁₁^–4, a nido speices

(d) B₆H₁₀ is derived from B₆H₆^4–, a nido speices

Correct option is (c)

7. The reaction of P₂O₅ with HNO₃ and HClO₄, respectively, gives

(a) NO₂ and ClO₂

(b) N₂O₅ and Cl₂O₆

(d) N₂O₅ and Cl₂O₇

Ans. (d)

Sol.

8. When crystals of sodium chloride are heated in the presence of sodium vapor, they turn yellow. This is due to the formation of

(a) Schottky defects

(b) Frenkel defects

(d) H-centres

Ans. (c)

Sol. When crystals of sodium chloride are heated in the presence of sodium vapour they turn yellow due to the formation of F-centres.

Correct option is (c)

9. One mole of an ideal gas is comlpressed from 5L to 2L at constant temperature. The change in entropy, in JK^–1, of the gas is ____________. (R = 8.314 JK^–1 mol^–1)

Ans. (–7.61)

Sol.

Correct answer is (–7.61)

10. The linear momentum of a particle described by the wavefunction e^–ikx is

(a) kh

(b) –kh

(c)

(d)

Ans. (d)

Sol. Linear momentum =

Correct option is (d)

11. For an elementary bimolecular gas phase reaction, activation energy is 5.5 kJ mol^–1. Enthalpy of activation, in kJ mol^–1, at 300K is ________. (R = 8.314 JK^–1 mol^–1)

Ans. (0.5116 kJ/mole)

Sol. Enthalpy of activation,

12. The titration of a strong acid with a strong base is represented by the plot

(a)

(b)

(c)

(d)

Ans. (c)

Sol. For strong acid vs strong base E = E⁰ + 0.0591 pH.

Plot of E vs volume of base will have same shape as volume

Similarly, for other plots too.

Correct option is (c)

13. Of the following inequalities, the criteria for spontaneity of a chemical reaction is/are

(a) (i) only

(b) (ii) only

(d) (i) and (iii)

Ans. (d)

Sol. Correct criterion, is

Correct option is (d)

14. A protein sample consists of an equimolar mixture of ribonuclease (molar mass = 13.7 kg mol^–1), hemoglobin (molar mass = 15.5 kg mol^–1), and myoglobin (molar mass = 17.2 kg mol^–1). The statement that is true about the weight-average molar mass , the number-average molar mass , and the polydispersity index (PDI) for this sample is

(a)

(b)

(c)

(d)

Ans. (a)

Sol. M₁ = 13.7

M₂ = 15.5

M₃ = 17.2

N₁ = N₂ = N₂ = N

P.D.I. =

Correct option is (a)

15. The band structure given below represent a

(a) n-type semiconductor formed by doping Si with B

(b) n-type semiconductor formed by doping Si with P

(d) p-type semiconductor formed by doping Si with B

Ans. (d)

Sol. p-type semiconductor formed by doping Si with B

Correct option is (d)

16. The experimental ionization energies of hydrogen and helium atoms in their ground states are, respectively, 13.6 eV and 24.6 eV. The ground state energy of helium atom, in eV, is

(a)

(b) –4(13.6) – 24.6

(c)

(d) –2(13.6) – 24.6

Ans. (b)

Sol.

I.p. hydrogen = 13.6 V

I.p. Hecting = 24.6 eV

Ground state for He = –4(13.6) – 24.6

Correct option is (b)

17. Ring flipping of the compound in the following conformation leads to

(a)

(b)

(c)

(d)

Ans. (b)

Sol.

On ring flipping axial bond convert into equatorial and quatorial convert into axial bond.

Correct option is (b)

18. The total number of lines expected (due to spin-spin coupling of proton with fluorine and deuterium nuclei) in the ¹H NMR spectrum of the following compound is ___________.

Ans. (6)

Sol.

multiplicity [2NI_F + 1] [2NI_D + 1]

Correct answer is (6)

19. The compound in 'R' configuration is

(a)

(b)

(c)

(d)

Ans. (a)

Sol.

Correct option is (a)

20. The most suitable reagent for performing the following transformation, is

(a) LiAlH₄

(b) H₂, Pd/C

(d) Li, Liq. NH₃

Ans. (c)

Sol.

Staudinger reaction, it does not affect the other functional groups.

Correct option is (c)

21. The major product obtained in the following reaction, is

(a)

(b)

(c)

(d)

Ans. (d)

Sol.

22. The Favourable transition state leading to the formation of the product in the following reaction, is

(a)

(b)

(c)

(d)

Ans. (d)

Sol.

Correct option is (d)

23. The major product of the following reaction is,

(a)

(b)

(c)

(d)

Ans.

Sol.

Correct option is (d)

24. The major product obtained in the following reaction, is

(a)

(b)

(c)

(d)

Ans. (a)

Sol.

Correct option is (a)

25. The major product formed in the following reaction, is

(a)

(b)

(c)

(d)

Ans. (c)

Sol.

Correct option is (c)

26. The Larmor frequency of ¹H at 1 Tesla (T) is 42.57 MHz. If the magnetogyric ratios for ¹H and ¹³C are 26.75 × 10⁷ rad T^–1 s^–1 and 6.72 × 10⁷ rad T^–1 s^–1, respectively, the Larmor frequency of ¹³C, in MHz, at 1 Tesla will be ___________

Ans. (10.6)

Sol.

Correct answer is (10.6)

27. At 1 bar and 298K, for the process , the is 200 J mol^–1 and is –2×10^–6 m³ mol^–1. The minimum pressure, in bar, at which the process becomes spontaneous at 298K is _______. (1 bar = 10⁵ Pa).

Ans. (1001)

Sol.

For reaction to be spontaneous < 0

or to find minimum pressure at which reaction become spontaneous, we can put = 0

= V_m (P₂ – P₁)

0 – 200 = – 2 × 10^–6 (P₂ – 10⁵)

10⁸ = P₂ – 10⁵

P₂ = 10⁵ + 10⁸

P₂ = 10⁵ (1 + 1000) Pa

P₂ = 1001 × 10⁵ Pa = 1001 bar

Correct answer is (1001)

28. The reaction, , is first order in both the directions. The forward and reverse rate constants are and 1.04×10^–3s^–1, respectively. The relaxation time for this reaction, in seconds, in a temperature jump experiement is ___________

Ans. (684.93)

Sol.

K₁ = 4.2 × 10^–4s^–1; K₂ = 1.04 × 10^–3s^–1

29. Adsorption of CO on charcoal at 273K follows Langmuir isotherm. A plot of P(kPa)/V(cm³) versus P (kPa) is linear with a slope of 0.01 y-intercept of 0.5. The equilibrium constant, K (kPa^–1), for the adsorption is __________.

Ans. (0.02)

Sol.

or K = 0.02

Correct answer is (0.02)

30. For the following reaction,

if steady state approximation can be applied on [I], the observed rate constant of product formation, in L mol^–1 s^–1, will be __________

Ans. (100)

Sol.

So, rate constant of product formation is

Correct answer is (100)

31. The correct set of infra-red spectral bands (in cm^–1) for the stretching mode of the given carbonyl complex is

(a) 1827, 1783, 1766

(b) 1973. 1827, 1794

(d) 1960, 1918

Ans. (a)

Sol. All carbonyl are µ²-bridging and range of bridging 1720 – 1850 cm^–1

Correct option is (a)

32. The ¹⁹F NMR spectrum of ClF₃ when measured at –60ºC will be observed as a

(a) singlet

(b) doublet

(d) doublet of doublet and a doublet of triplet

Ans. (c)

Sol.

Correct option is (c)

33. Among the given platinum(II) complexes, the one that is thermally the most unstable is

(a)

(b)

(c)

(d)

Ans. (c)

Sol. In contrast to s, p block metal, transition metal possess vaccant d-orbital which involve kinetically facile reaction such as -H elimination, alkene insertion, etc. which leads to transformation of alkyl ligand into other group.

Hence, compound which have -hydrogen w.r.t. metal are unstable.

Correct option is (c)

34. The shapes of XeF₅⁺ and XeF₅^–, respectively, are

(a) pentagonal planar and square pyramidal

(b) pentagonal planar and trigonal bipyramidal

(d) square pyramidal and pentagonal planar

Ans. (d)

Sol.

Correct option is (d)

35. Sodium salt of pseudohalogens, X, Y and Z form colorless solutions in water. Solution of X decolorizes I₃^– solution with brisk effervescence. Solution of Y gives an intense red colour on reaction with Fe³⁺ solution. Solution of Z gives an intese blue color on reaction with a solution containing Fe³⁺ and Fe²⁺ ions. The pseudohalogens X, Y and Z respectively are

(a)

(b)

(c)

(d)

Ans. (b)

Sol.

Correct option is (b)

36. On reacting 1.55g of a diol with an excess of methylmagnesium iodide, 1.12L (corrected to STP) of methane gas is liberated. The molecular mass (g mol^–) of the diol is _________

Ans. (62)

Sol. di – ol + excess MeMgBr 2CH₄

Mg(molecular weight) = 2 × 22.4L CH₄

Correct answer is (62)

37. The structure of the compound having the following characteristics spectral data, is IR : 1690 cm^–1.

¹H-NMR : 1.30 (3H, t, J = 7.2 Hz); 2.41 (2H, q, J = 7.2 Hz); 2.32 (3H, s); 7.44 (1H, t, J = 7.0 Hz); 7.57 (1H, dt, J = 7.0, 3.0 Hz); 7.77 (1H, t, J = 3.0 Hz); 7.90 (1H, dt, J = 7.0, 3.0 Hz); EI mass : m/z 119 (100%); 57 (80%)

(a)

(b)

(c)

(d)

Ans. (a)

Sol.

Correct option is (a)

38. The major products X and Y formed in the following formed in the following synthetic scheme, are

(a)

(b)

(c)

(d)

Ans. (b)

Sol.

Correct option is (b)

39. The major product S and T formed in the following synthetic schemem, are

(a)

(b)

(c)

(d)

Ans. (b)

Sol.

Correct option is (a)

40. Among the following, the transformation(s) that can be accomplished using umpolung concept is(are)

(a) (i) and (iii)

(b) (ii) and (iv)

(d) (i) and (ii)

Ans. (d)

Sol. "Umpolung concept" polarity inversion in organic chemistry is the chemical modification of a functional group with the aim of the reversal of polarity of that group.

Correct option is (d)

41. A disaccharide does NOT give a positive test for Tollen's reagent. Upon acidic hydrolysis, it gives an equimolar mixture of two different monosaccharides, both of which can be oxidized by bromine water. This disaccharide is

(a)

(b)

(c)

(d)

Ans. (d)

Sol. Disaccharide (a), (c) and (d) have glycose linkages at both the anomeric carbons, hence they give negative Tollen's test. While as disaccharide (b) gives positive Tollen's test. Upon hydrolysis disaccharide (a) is hydrolysed into D-glucose and D-fractose. While as disaccharide (c) is converted into 2-moles of D-glucose. Disaccharided upon hydrolysis is converted in D-glucose and D-galactose both of which gives Br₂/H₂O test.

Correct option is (d)

42. The major products M and N in the following reaction sequence are

(a)

(b)

(c)

(d)

Ans. (a)

Sol.

Correct option is (a)

43. The major products P and Q in the following reaction sequence, are

(a)

(b)

(c)

(d)

Ans. (c)

Sol.

Correct option is (c)

44. The major product formed in the following reaction, is

(a)

(b)

(c)

(d)

Ans. (b)

Sol.

45. The following synthetic transformation can be achieved using

Reagents:

(p) (i) NH₂OH/H⁺, (ii) H₂SO₄

(q) NH₃/H⁺

(r) (i) NH₂OH/H⁺, (ii) NaOH

(a) p only

(b) p and q

(d) r only

Ans. (b)

Sol.

(P) = Beckmann rearrangement

(Q) = Schimst reaction

Correct option is (b)

46. Consider a two-state system at thermal equilibrium with equal degeneracy where the excited state is higher in energy than the ground state by 0.1 eV. The ratio of the population of the excited state to that of the ground state, at a temperature for which k_BT = 0.05 eV, is __________

Ans. (0.1353)

Sol.

47. Of the vibrational modes given below, the IR active mode(s) is(are)

(a) (ii) only

(b) (ii) only

(d) (ii) and (iii)

Ans. (d)

Sol.

Correct option are (ii) and (iii)

Correct option is (d)

48. A system is described by the following real wave function.

The probability (P) of finding the particle in a region dx around points I, II and III in the figure obeys the trend

(a) P(I) > P(II) > P(III)

(b) P(II) > P(III) > P(I)

(d) P(III) > P(I) > P(II)

Ans. (b)

Sol.

More region more probability, (P) II > III > I

Correct option is (b)

49. The temperature-composition (T-x) phase diagram of the two-component system made of X and Y is given below. At a temperature of 288K and starting at the point P, Y is added until the composition reaches S. Which of the following statements is NOTR TRUE?

(a) At P, the solid and liquid are present in almost equal proportions

(b) At Q, the system is all liquid

(d) At R, the liquid is pure X

Ans. (d)

Sol. At R, Y(s) + liquid is present

Correct option is (d)

50. For a system subjected to only P-V work, entropy is given by

(a) I and II

(b) I and IV

(d) II only

Ans. (b)

Sol. dG = – SdT + VdP dA = – SdT – PdV

Correct option is (b)

51. According to Irving-Williams series, the number of d electrons for the first row transition metal (M) ion having the highest overall stability constant (log ) for [M(EDTA)]^2– is ___________

Ans. (9)

Sol. For M²⁺ ions, the general trend in stability for complexes is,

This trend in stability is known as Irving-Williams series.

Hence, Cu²⁺ is more stable than other first row transition metals.

Therefore, the number of d-electrons for the first transition metal (M), i.e. Cu²⁺ ion having the highest overall stability constant (log ) for [M(EDTA)]^2–is 9.

Correct answer is 9.

52. The magnitude of the difference in the crystal field stabilization energies, in (irnoring pairing energy), of and is __________

Ans. (2.0 )

Sol.

53. The calculated and observed magnetic moments differ considerably for an aqua complex of a Lanthanide (III) ion as a result of low lying states of high J. The ion, among the following, is

(a) Ce³⁺

(b) Pr³⁺

(d) yb³⁺

Ans. (c)

Sol. The calculated magnetic moments for lanthanides have good agreement with observed values. For lanthanoids the value of is about 1000 cm^–1. However, λ value for Eu³⁺ is about 100 cm^–1 which is small value. Therefore, the agreement for Eu³⁺ is not very good.