GATE Chemistry — Physical Chemistry Questions & Answers
GATE 2007 — 18 Questions
Q1. The ground state term of ion is
Answer: (a) 3F
Q2. The dimension of Plank's constant is (M, L and T denote mass, length and time respectively)
Answer: (b) ML2T–1
Q3. The selection rules for the appearance of P branch in the rotational-vibrational absorption spectra of a diatomic molecule within rigid rotor-hormonic oscillator model are
Answer: (c) ∆v = +1 and ∆J = –1
Q4. Which of the following statements is NOT correct for a catalyst?
Answer: (d) It increase the activation energy of the reaction
Q5. Boric acid in aqueous solution in presence of glycerol behaves as a strong acid due to the formation of
Answer: (a) an anionic metal-chelate
Q6. A student recorded a polarogram of 2.0 mM Cd2+ solution and forgot to add KCl solution. What type of error do you expect in his results?
Answer: (c) Both migration current as well as diffusion current will be observed
Q7. The temperature of 54 g of water is raised from 15° C to 75° C at constant pressure. The change in the enthalpy of the system (given that JK–1 mol–1) C of water –75 is p, m
Answer: (b) 13.5 kJ
Q8. The specific volume of liquid water is 1.0001 g–1 g–1 mL and that of ice is L 0907 mL at 0°C. If the heat of fusion of ice at this temperature is 333.88 J g–1, the rate of change of melting point atm–1 of ice with pressure in deg will be
Answer: (a) –0.0075
Q9. For the reaction P + Q + R → S, experimental data for the measured initial rates is given below Expt. Initial Initial Initial Initial rate conc. P conc. conc. R (M s–1) (M) Q (M) (M) 1 0.2 0.5 0.4 8.0 × 10–5 3.2×10–4 2 0.4 0.5 0.4 3 0.4 2.0 0.4 1.28 × 10–3 4 0.1 0.25 1.6 4.0×10–5 The order of the reaction with respect to P, Q and R respectively is
Answer: (c) 2, 1, 1
Q10. Sucrose is converted to a mixture of glucose and fructose in a pseudo first order process under alkaline conditions. The reaction has a half life of 28.4 min. The time required for the reduction of a 8.0 mM sample of sucrose to 1.0 mM is
Answer: (a) 56.8 min.
Q11. The entropy of mixing of 10 moles of helium and 10 moles of oxygen at constant temperature and pressure, assuming both to be ideal gases, is JK–1 JK–1
Answer: (b) 5.8 JK–1 JK–1
Q12. The ionisation potential of hydrogen atom is 13.6 eV. The first ionization potential of a sodium atom, assuming that the energy of its outer electron can be represented by a H-atom like model with an effective nuclear charge of 1.84, is
Answer: (c) 5.1 eV
Q13. The quantum state of a particle moving in a circular path in a plane is given by ( ) eimφ,m=0,±1,±2 ψ (φ(= 1/ 2π m When a perturbation H P = cosφ is applied (P 1 is constant), what will be the first order correction to the energy of the mth state
Answer: (a) 0
Q14. Assuming H and HD molecules having equal 2 bond lengths, the ratio of the rotational partition functions of these molecules, at temperatures above 100 K is
Answer: (a) 3/8
Q15. N non interacting molecules are distributed among three non degenerate energy levels ε = 0 ε = 1.38 × 10–21 J and ε = 2.76 × 10–21 J at 100 1 2 K. If the average total energy of the system at this temperature is 1.38 × 10–18 J, the number of molecules in the system is
Answer: (a) 1000
Q16. The J = 0 → 1 rotational transition for occurs at 500.72 GHz. Assuming the molecule to be a ri gid rotor, the J = 3 → 4 transition occurs at
Answer: (c) 16.7 cm–1
Q17. The rate constants of two reactions at temperature T are k(T) and k(T) and the 1 2 corresponding activation energies are E and 1 E with E > E. When temperature is raised 2 2 1 from T to T, which one of the following 1 2 relations is corr ect? k (T ) k (T ) k (T ) k (T ) 1 2 2 2 1 2 2 2
Answer: (d) 1 2 < 2 2 k (T ) k (T ) k (T ) k (T ) 1 1 2 1 1 1 2 1
Q18. The mono protonation of adenine (X) in acidic solution mainly occurs at
Answer: (b) position 2
GATE 2008 — 8 Questions
Q19. The correct statement about C is 60
Answer: (a) C is soluble in benzene 60
Q20. The highest occupied molecular orbital of HF is
Answer: (d) nonbonding
Q21. The structure of the complexes [Cu(NH)] 34 (ClO) and [Cu(NH)](ClO) in solution 42 34 4 respectively are
Answer: (c) octahedral and trigonal bipyramidal
Q22. NaCl is crystallised by slow evaporation of its aqueous solution at room temperature. The correct statement is
Answer: (d) The nature of defects will depend upon the concentration of the solution and its rate of evaporation.
Q23. If ClF were to be stereochemically rigid, its 19F 3 19F NMR spectrum (I for = 1/2) would be (assume that Cl is not NMR active)
Answer: (a) a doublet and a triplet
Q24. The IR stretching frequencies for the compound X are as follows : 3300–3500 (s, br); 3000 (m); 2225 (s); 1680 (s). O H CN OH X The correct assignment of the absorption bands is v (OH) =3300−3500;v (CH) =3000;v (CN)
Answer: (b) =2225;v(CO)=1680; v(OH)=3300−3500;v(CH)=3000;v(CN)
Q25. According to the Debye-Huckel limiting law, the mean activity coefficient of 5×10–4 mol kg–1 aqueous solution of CaCl at 25 °C is (the 2 Debye-huckel constant 'A' can be taken to be 0.509)
Answer: (d) 0.91
Q26. Physisorbed particles undergo desorption at 27 mol–1. °C with an activation energy of 16.628 kJ Assuming first-order process and a frequency factor of 1012 Hz, the average residence time (in seconds) of the particles on the surface is 10–10 10–11
Answer: (a) 8 ×
GATE 2009 — 13 Questions
Q27. The NMR spectrum of PS consists of 4 3
Answer: (c) a doublet and a quartet
Q28. Among the following, the reaction that is accompanied by a decrease in the entropy is
Answer: (a) N(g) + 3H(g) → 2NH (g) 2 2 3
Q29. The lowest allowed energy is equal to zero for
Answer: (b) a rigid rotor
Q30. According to the Debye–Huckel limiting law, if the concentration of a dilute aqueous solution of KCI is increased 4 – fold, the value of In ϒ± (ϒ± is the molal mean ionic activity coefficient) will
Answer: (b) increase by a factor of 2
Q31. For the parallel first order reaction shown below the value of K is 1 ×10–4 s–1. If the reaction 1 starts from X, the ratio of the concentrations of Y and Z at any given time during the course of [Y] 1 the reaction is found to be = The value [Z] 4 of K is 2 10–4 s–1 10–5s–1
Answer: (c) 4 × 10–4s–1
Q32. In the photochemical reaction formation of the compound X can be inferred by the disappearance of the 'H NMR signal at [1H NMR spectrum of the starting material : δ 9.7 (1H, s) 7.8 (1H, d, J 8.0 Hz), 7.1 – 6.8 (2H, m), 3.9 (3H, s), 2.5 (3H, s) ppm]
Answer: (a) δ 9.7 ppm
Q33. The rotational Raman spectrum of shows a 2 series of Stokes lines at 19230.769 cm–1, 19227.238 cm–1 and 19223.707 cm–1. The rotational constant for 19F in GHz is 2
Answer: (d) 3.531 59
Q34. Given that the standard molar enthalpies of formation of NO(g) and NO(g) are, 2 respectively, 90.3 kJ mol–1 and 33.2 kJ mol–1, the enthalpy change for the reaction 2NO(g) + O(g) → 2NO(g) is 2 2
Answer: (c) –114.2 kJ
Q35. The free energy change (∆G) of 1 mole of an ideal gas that is compressed isothermally from I atm to 2 atm is
Answer: (a) RTIn2
Q36. Two liquids B and C form an ideal solution. In the figure below, the vapour pressure P of this solution is shown as a function, X, of B component B. Given a state of this vapour-liquid mixture whose overall composition corresponds to point E in the figure, the mole fraction of B in the vapour phase is approximately.
Answer: (d) 0.80
Q37. The reducible representation corresponding to the three translational degrees of freedom, is Γ , is tr
Answer: (b) 3, –1, 1, 1
Q38. The overall rate constant (k ) for the overall formation of P can be expressed as
Answer: (a) kk/k
Q39. The overall activation energy (E ) for the A, overall formation of P can be expressed as E .E
Answer: (c) E + E – E
GATE 2010 — 9 Questions
Q40. Among the following, a pair of resolvable configurational enanliomers is given by
Answer: (d) trans-1,3-dimethylcyclohexane
Q41. The decreasing order of the reactivity of the following compounds towards electrophiles is I II III
Answer: (c) III > II > I
Q42. The molar entropy of crystalline CO at absolute zero is
Answer: (c) Rin 2
Q43. For an ideal gas
Answer: (b) (∂P/∂T) (∂T/∂V) (∂V/∂P) = –1 V P T
Q44. Among W (work), Q (heat), U (internal energy) and S (entropy)
Answer: (d) W and Q are path functions but U and S are state functions
Q45. The change in entropy when two moles of Argon gas are heated at constant volume from 300 K to 500 K is K–1 mole–1 K–1 mole–1
Answer: (d) 12.74 J
Q46. The specific rate constant of decomposition of a compound is represented by 12000 In k = 5.0 – T The activation energy of decomposition for this compound at 300 K is
Answer: (a) 24 kcl/mole
Q47. Based on the above diagram:
Answer: (d) A represents the change in chemical potential as a function of temperature for the gas phase, B for solid and C for the liquid
Q48. From the same diagram
Answer: (d) D represents melting point, F boiling point and E sublimation point
GATE 2011 — 11 Questions
Q49. The reaction of solid XeF with AsF in 1:1 2 5 ratio affords
Answer: (c) [XeF]+ [AsF6]–
Q50. The region of electromagnetic spectrum employed in the electron spin resonance (ESR) spectroscopy is
Answer: (b) microwave
Q51. For a given first order reaction, the reactant 1/4th reduces to of its initial value in 10 minutes. The rate constant of the reaction is min–1
Answer: (a) 0.1386 min–1
Q52. The wave function for a Harmonic oscillator Nxexp(–αx2/2) described by has
Answer: (b) one maximum, are minimum only
Q53. According to the Ehrenfest classification of phase transitions, the above diagram refers to
Answer: (b) First order phase transition
Q54. According to conventional transition state theory, for elementary bimolecular reactions, the molar entropy of activation ∆#So is
Answer: (b) zero
Q55. The activity of water at 11 bar and 298 K is
Answer: (c) 0.998
Q56. For the process 1Ar (300 K, 1 bar) → 1 Ar (200 K, 10 bar) assuming ideal gas behavior, the change in molar entropy is K–1 mol–1 K–1 mol–1
Answer: (a) –27.57 J
Q57. The wave function for a quantum mechanical particle in a 1-dimensional box of length ‘a’ is πx given by ψ = A sin a The value of ‘A’ for a box of length 200 mm is 4×104 (nm)2
Answer: (d) 0.1 (nm)–1/2
Q58. For a 1 molal aqueous NaCl solution, the mean ionic activity coefficient (γ) and the Debye- ± Huckel Limiting Law constant (A) are related as
Answer: (d) γ = 10–A ± ± NaCl→Na++Cl−
Q59. For the concentration cell M M+ (aq, 0.01 mol dm–3 M+ (aq, 0.1 mol dm–3) M the EMF (F) of the cell at a temperature (T) equals RT RT
Answer: (a) 2.303
GATE 2012 — 12 Questions
Q60. If Δy and Δpy are the uncertainties in the y- coordinate and the y component of the momentum of a particle respectively, then, according to uncertainty principle ΔyΔpy is h (ћ = and h is Planck’s constant) 2π ℏ
Answer: (d) ≥ 2
Q61. The angular part of the wave function for the electron in a hydrogen atom is proportional to sin2θ cosθ.e2iφ. The values of the azimuthal quantum number (l) and the magnetic quantum number (m ) are, respectively
Answer: (c) 3 and 2
Q62. Let and φCdenote the wave functions of the x z 2p and 2p orbitals of carbon, respectively, x z and φOand φO represent the wave functions of x z the 2p and 2p orbital's of oxygen, x z respectively. If c and c are constants used in 1 2 linear combinations and the CO molecule is oriented along the z axis, then, according to molecular orbital theory, the π-bonding molecular orbital has a wave function given by
Answer: (d) cφC+cφO 1 x 2 z 1 x 2 x
Q63. The bond that gives the most intense band in the infrared spectrum for its stretching vibration is
Answer: (c) O – H
Q64. If x and x are the respective mole fractions of A B A and B in an ideal solution of the two and T, A T, T are the fusion temperatures of pure A, B pure B and the ideal solution respectively, then º –∆H 1 1 f us(B)
Answer: (d) 1 – x = exp – B R T T A
Q65. At 298 K, the EMF of the cell Pt│H (1bar)│H+(solution)║Cl─│Hg Cl │Hg is 2 2 2 0.7530 V. The standard potential of the calomel electrode is 0.2802 V. If the liquid junction potential is zero, the pH of the solution is
Answer: (c) 8.0
Q66. Consider the reaction H + C H → C H 2 2 4 2 6 The molecular diameters of H and CH are 2 2 4 1.8 Å and 3.6 Å respectively. The pre- exponential factor in the rate constant m3 (mole)–1 calculated using collision theory in s–1 is approximately. 1 8k T 2 (For this reaction at 300 K, B N = A πµ 1.11×1027 m(mole)–1s–1, where the symbols have their usual meanings)
Answer: (a) 2.5×108
Q67. The molecular partition function of a system is 3 3 k T 2 8πmk T 2 given by q(T)= B B , where hc h2 the symbols have their usual meanings. The heat capacity at constant volume for this system is
Answer: (a) 3R
Q68. For the titration of a 10 mL (aq) solution of CaCO, 2 mL of 0.001 M NaEDTA is required 3 2 to reach the end point. The concentration of CaCO (assume molecular weight of CaCO = 3 3 100) is
Answer: (c) 5 × g/mL
Q69. If a mixture of NaCl, conc. HSO and KCrO 2 4 2 2 7 is heated in a dry test tube, a red vapour (P) is formed. This vapour (P) dissolves in aqueous NaOH to form a yellow solution, which upon treatment with AgNO forms a red solid (Q). P 3 and Q are, respectively
Answer: (d) CrO Cl and Ag CrO 2 2 2 4
Q70. The INCORRECT statement about Zeise’s salt is
Answer: (c) All the Pt─Cl bond lengths in Zeise’s salt are equal
Q71. The rotational constant (usually denoted as B) for the oxygen molecule is
Answer: (a) 1.2 cm─1
GATE 2013 — 9 Questions
Q72. Two trial wave functions φ = c x(a – x) and φ 1 1 2 x2(a x)2 = c x(a – x) + c – give ground state 1 2 energies E and E, respectively, for the 1 2 microscopic particle in a 1-D box by using the variation method. If the exact ground state energy is E , the correct relationship between 0 E , E and E is 0 1 2
Answer: (c) E < E< E
Q73. A 2 L vessel containing 2 g of H gas at 27°C is 2 connected to a 2 L vessel containing 176 g of CO gas at 27°C. Assuming ideal behavior of 2 H and CO, the partial pressure of H at 2 2 2 equilibrium is ________ bar. 110
Answer: (d) K = 4S3γ3 SP ± SP ±
Q74. The infrared spectrum of HCl gas shows an absorption band centered at 2885 cm–1. The zero point energy of HCl molecule under harmonic oscillator approximation is
Answer: (b) 2.8665 × 10–20 J
Q75. For a reaction of the type X↽ ⇀Y, the k 2 correct rate expression is ([X]0 and [X] correspond to the concentrations of X at time t = 0 and t = t, respectively) d[X]
Answer: (b) – = (k + k )[X] – k [X] 1 2 2 0 dt d[X]
Q76. The temperature dependence of partition functions are as follows: 3 Translation ∝ T 2 T0 Translation ∝ Translation ∝ T(linear molecule) 3 Translation ∝ T2 According to the conventional transition state theory (CTST), the temperature dependence of the Arrhenius pre-exponential factor for a reaction of the type given below is linear molecule + linear molecule non-linear transition state → products
Answer: (a) T–1
Q77. The increasing order of melting points of the halides NaCl, CuCl and NaF is
Answer: (a) CuCl < NaCl < NaF
Q78. Among the following octahedral complexes, the one that has the highest enthalpy of hydration is
Answer: (d) 2 6 2 6
Q79. The ground state term of is 2 6
Answer: (c)
Q80. For the determination of solubility product (K ) of Fe(OH), the appropriate cell SP representation and its emf are, respectively,
Answer: (b) – 3 0.750 V
GATE 2014 — 8 Questions
Q81. Consider the reaction: ↽⇀ A + B C The unit of the thermodynamic equilibrium constant for the reaction is L−1 mol−1
Answer: (b) L
Q82. The value of the magnetic quantum number of a p orbital is x
Answer: (d) undefined
Q83. In atomic absorption spectroscopy, the atomization process utilizes
Answer: (a) flame
Q84. The correct order of IR stretching frequency of the C=C in the following olefins is
Answer: (c) III > II > I
Q85. The correct order of the rate of solvolysis for the following chlorides in acetic acid is
Answer: (b) III > II > I
Q86. ψ = Nr(6 – Zr)e–Zr/3 cosθ, is a proposed hydrogenic wave function, where Z = Atomic number, r = radial distance from the nucleus, θ = azimuthal angle, N is a constant. The INCORRECT statement about ψ is
Answer: (b) two radial nodes are present in ψ
Q87. A plot of osmotic pressure against L–1) concentration (g of a polymer is constructed. The slope of the plot
Answer: (a) increases with increase in temperature
Q88. is preferred in photosynthesis by chlorophyll because
Answer: (b) it has weak spin-orbit coupling
GATE 2015 — 11 Questions
Q89. For an ideal gas with molar mass M, the molar translational entropy at a given temperature is proportional to
Answer: (a) M3/2
Q90. Which of the following properties are characteristic of an ideal solution? (i) (∆ G) is negative mix T,P (ii) (∆ S) is positive mix T,P (iii) (∆ V) is positive mix T,P (iv) (∆ H) is negative mix T,P
Answer: (b) (i) and (ii)
Q91. Which one of the following statements is INCORRECT?
Answer: (b) Frenkel defect is an anion vacancy and a cation interstitial.
Q92. The correct order of reactivity of p- halonitrobenzenes in the following reaction is
Answer: (b) p-fluoronitrobenzene > p-chloronitrobene > p- bromonitrobenzene > p-iodonitrobenzene
Q93. Tollen's test is NEGATIVE for
Answer: (d) sucrose
Q94. The process given below follows the Langmuir 2 adsorption isotherm. A (g)↽ k 1 ⇀ A 2 k – ads 1 If θ denotes the surface coverage and P denotes the pressure, the slope of the plot of 1/θ versus 1/ Pis )2
Answer: (b) 1/K eq eq )1/2
Q95. The solubility product of AgBr(s) is 5×10-13 at 298 K. if the standard reduction potential of the half-fell, E0 - is 0.07 V, the AgAgBr(s)Br standard reduction potential, E0 (in volts) Ag+Ag is ________. 142
Answer: (d) k k< k 3 2 1 3 < 1 2
Q96. The potential energy (PE) versus reaction coordinate diagrams for electron transfer reactions with rate constants k , k and k , are 1 2 3 given below. The increasing order of the rate constants is 142 / 288
Answer: (a) 2.0036 and 1
Q97. The percent transmittance of 8 × 10–5 M solution of KMnO is 39.8 when measured 510 4 nm in a cell of path length of 1 cm. The absorbance and the molar extinction coefficient M–1 cm–1) (in of this solution are, respectively,
Answer: (c) 0.4 and 5000
Q98. Ammonolysis of SCl in an inert solvent gives 2 2
Answer: (d) SN 2 2 4 4 4
Q99. When one CO group is replaced by PPh in 3 [Cr(CO)], which one of the following 6 statement is TRUE?
Answer: (c) The Cr-C bond length decreases and CO bond length increases
GATE 2016 — 8 Questions
Q100. At pH 7.2 and 10 Ton oxygen partial pressure, the extent of O binding is 2
Answer: (c) High for myoglobin and low for hemoglobin
Q101. The linear momentum of a particle described by the wave function e–ikx is
Answer: (d) –kℏ
Q102. Of the following inequalities, the criterion/criteria for spontaneity of a chemical reaction is/are (i) (∆G) < 0 (ii) (∆U) > 0 (iii) (∆S) T,P S,V U,V
Answer: (d) (i) and (iii) Ist
Q103. A protein sample consists of an equimolar mixture of ribonuclease (molar mass = 13.7 kg mol–1) mol– , hemoglobin (molar mass = 15.5 kg 1), and myoglobin (molar mass = 17.2 kg mol–2). The statement that is true about the weight- ( ) average molar mass M ,the number- w ( ) average molar mass M , and the n polydispersity index (PDI) for this sample is
Answer: (a) M >M =15.5kgmol–1andPDI>1 w n
Q104. The NMR spectrum of ClF when measured 3 at –60 ºC will be observed as a
Answer: (c) Doublet and a triplet
Q105. Sodium salts of pseudohalogens X, Y, and Z form colourless solutions in water. Solution of X decolorizes I˗ solution with brisk 3 effervescence. Solution of Y gives an intense red colour on reaction with Fe3+ solution. Solution of Z gives an intense blue colour on Fe3+ reaction with a solution containing and Fe2+ ions. The pseudohalogens X, Y, and Z, respectively, are
Answer: (b) N-, CNS-, and CN˗ 3 N-, CN˗, CNS-
Q106. The temperature-composition (T-x) phase diagram of the two-component system made of X and Y is given below. At a temperature of 288 K and starting at the point P, Y is added until the composition reaches S. Which of the following statements is NOT TRUE?
Answer: (d) At R, the liquid is pure X.
Q107. For a system subjected to only P-V work, entropy is given by
Answer: (b) (i) and (iv)
GATE 2017 — 10 Questions
Q108. Consider N particles at temperature T, pressure P, volume V and chemical potential µ having energy E. The parameters that are kept constant for a canonical ensemble are
Answer: (a) N, V, T
Q109. For ortho-hydrogen, the nuclear wavefunction and the rotational quantum number, respectively, are
Answer: (b) Symmetric and odd
Q110. m and m are the slopes (dp/dT) of the solid- 1 2 liquid equilibrium lines in the P-T phase diagrams of HO and CO, respectively, For 2 2 P<10 atm, the values of m and m are 1 2
Answer: (d) m < 0 and m > 0 1 2 1 2
Q111. Consider an ideal gas of volume V at temperature T and pressure P. If the entropy of the gas is S, the partial derivative (∂P/∂S) is V equal to
Answer: (c) –(∂T/∂V)
Q112. The wavelength associated with a particle in one-dimensional box of length L is (n refers to the quantum number)
Answer: (a) 2L/n
Q113. The electronic ground state term for the chromium ion in [Cr(CN)]4– is 6
Answer: (b) 3H
Q114. The lanthanide ion that exhibits color in aqueous solution is
Answer: (b) Eu (III)
Q115. The V resonance Raman stretching C-O cm–1) frequency (in of the O of the coordinated 2 to iron centre in oxy-hemoglobin is nearly
Answer: (a) 1100
Q116. The characteristic feature of an electron spin resonance (ESR) spectrum of frozen aqueous solution of CuSO. 5HO at 77 K is 4 2
Answer: (b) g
Q117. The 13C NMR spectrum of acetone-d has a signal 6 at 30 ppm as a septet in the intensity ratio
Answer: (b) 1 : 3 : 6 : 7 : 6 : 3 : 1
GATE 2018 — 3 Questions
Q118. A one-dimensional anharmonic oscillator is treated by perturbation theory. The harmonic oscillator is used as the unperturbed system 1 and the perturbation is γx3 (γ is a constant). 6 Using only the first order correction, the total ground state energy of the anharmonic oscillator is (Note: For a one-dimensional harmonic 1 1 α 4 kµ 2 oscillator ψ(x)= e–ax2;a= ) 0 π h 1 k2 1 k2 1 1 γ
Answer: (a) ℏ
Q119. Spectroscopic ground state term symbols of cobalt ions in [Co(H2O)6]2+ and [CoCl4]2–, respectively, are
Answer: (a) 2Tg and 4A 1 2
Q120. Second-order rate constant for the reaction [Co(NH)X]n+ between (n = 3 for X = NH and 35 3 Cl–) [Cr(HO)]2+ HO; n = 2 for X = and at 2 2 6 room temperature varies with the X as
Answer: (b) Cl– > HO > NH 3 2 2 3 Cl– Cl–
GATE 2019 — 5 Questions
Q121. The INCORRECT statement about the interhalogen compound ICl is : 3
Answer: (b) Geometry around the iodine is tetrahedral in solid-state.
Q122. The INCORRECT statement about the silicones is :
Answer: (a) They are thermally unstable because of the Si–C bond.
Q123. In Freundlich isotherm, a linear relationship is obtained in the plot of (θ = surface coverage and p = partial pressure of the gas)
Answer: (a) θ vs p
Q124. Micelle formation is accompanied by the
Answer: (b) increase in overall entropy mostly due to increase in solvent entropy.
Q125. A complex is composed of one chromium ion, three bromides and six water molecules. Upon addition of excess AgNO, 1.0 g aequeous 2 solution of the complex gave 0.94 g of AgBr. The molecular formula of the complex is (Atomic weight : Cr = 52, Br = 80, Ag = 108, O = 16 and H = 1)
Answer: (b) [Cr(HO)Br]Br•HO 2 5 2 2
GATE 2020 — 8 Questions
Q126. Absolute stereochemistry of the given compound is :
Answer: (d) 4aS, 8aR
Q127. A solution containing a metal complex absorbs at 480 nm with molar extinction coefficient of mol–1 cm–1. 15000 L If the path length of the cell is 1.0 cm and transmittance is 20.5% the L–1) concentration (in mol of the metal complex is :
Answer: (c) 4.59 × 10–5
Q128. Among the following linear combination of atomic orbitals, the CORRECT representation of the lowest unoccupied π-molecular orbital of butadiene is :
Answer: (b) Ψ = 0.602 φ – 0.372 φ + 0.372φ + 0.602φ 1 2 3 4
Q129. The character table for a pyramidal AB 3 molecule of C point group is given below : 3v C E 2C 3σ 3v 3 v A 1 1 1 x2+y2,z2 1 z A 1 1 -1 R 2 z E 2 -1 0 (x,y)(Rx,Ry) (x2-y2,xy)(xz,yz) The reducible representation of pyramidal AB 3 is C E2 C 3σ 3v 3 v Γ 12 0 2 The CORRECT option representing all the normal Raman active modes of pyramidal AB 3 is :
Answer: (d) 2A + 2E 1
Q130. The rate of solvolysis of the given compounds is in the order.
Answer: (a) T > R > Q > S > P
Q131. In the electronic absorption spectrum of an aqueous solution of [Ni(NH)]2+ , a very weak 36 band is observed between the bands due to the transitions 3A → 3T and 3A → 3T (F). 2g 2g 2g 1g The transition responsible for the very weak band is (Given atomic number of Ni is 28)
Answer: (c) → 2g g
Q132. The experimental magnetic moment (3.4 BM) Eu3+ of a hydrated salt of at 27 °C is significantly different from the calculated value. The difference is due to (Given : atomic number of Eu is 63)
Answer: (d) pairing of electrons in/ – orbitals.
Q133. Adsorption of N on TiO was carried out at 2 2 z z(z=p/p0) 75K. A plot of versus gives a (1−z)y 10–6 mm–3 straight line with an intercept, 4.0 × and slope, 1.0 × 10–3. The volume (rounded off to the nearest integer) corresponding to the monolayer coverage is :
Answer: (a) 996 mm3
GATE 2021 — 6 Questions
Q134. An organic compound exhibits the [M+2]+ [M+4]+ and peaks in the intensity ratio 1:2:1 in the mass spectrum, and shows a singlet 1H at δ 7.49 in the NMR spectrum in CDCl. 3 The compound is:
Answer: (a) 1,4-dichlorobenzene
Q135. The equilibrium constant for the reaction 3NO (g) ↽⇀ NO(g) + NO(g) 2 2 at 25 °C is closest to: mol–1 K–1] [ΔG° = –104.18 kJ; R = 8.314 J 1018
Answer: (b) 1.8 ×
Q136. The yellow colour of an aqueous solution of KCrO changes to red-orange upon the 2 4 addition of a few drops of HCl. The red-orange complex, the oxidation state of its central element(s), and the origin of its color, respectively, are:
Answer: (b) dichromate ion, +6 and +6, charge transfer
Q137. The metal borides that contain isolated boron atoms are:
Answer: (a) TcB and ReB
Q138. In an electrochemical cell, ions in AgNO 3 are reduced to Ag metal at the cathode and Cu Cu2+ is oxidized to at the anode. A current of 0.7 A is passed through the cell for 10 min. The mass (in grams) of silver deposited and copper dissolved, respectively, are: mol–1, [Faraday Constant = 96,485 C Atomic Weight of Ag = 107.9, Atomic Weight of Cu = 63.55]
Answer: (a) 0.469 and 0.138
Q139. Hexane and heptane are completely miscible. At 25°C, the vapour pressures of hexane and heptane are 0.198 atom and 0.06 atom, respectively. The mole fractions of hexane and heptane in the vapor phase for a solution containing 4 M hexane and 6 M heptane, respectively, are:
Answer: (b) 0.400 and 0.600
GATE 2022 — 4 Questions
Q140. The ν resonance Raman stretching O–O (cm-1) frequency of the coordinated dioxygen in oxy-hemoglobin and oxy-hemocyanin appears, respectively, nearly at
Answer: (d) 744 and 1550 251
Q141. Adsorption of a gas with pressure P on a solid obeys the Langmuir adsorption isotherm. For a fixed fractional coverage, the correct relation between K and P at a fixed temperature is [K = k/k, k and k are the rate constants for a b a b adsorp tio n and desorption, respectively. Assume non-dissociative adsorption.] ∝ P–1/2 ∝
Answer: (c) K ∝
Q142. Three different crystallographic planes of a unit cell of a metal are given below (solid circles represent atom). The crystal system of the unit cell is
Answer: (d) orthorhombic
Q143. The CORRECT statement regarding the following three normal modes of vibration of SO3 is I II III
Answer: (b) (I) is infrared inactive while (II) and (III) are infrared active
GATE 2023 — 5 Questions
Q144. For an ideal gas, the molecular partition function in the canonical ensemble, that is (V), proportional to the system volume is the
Answer: (a) Vibrational partition function
Q145. For the Lindemann-Hinshelwood mechanism of gas phase unimolecular reactions, the true statement (s) is (are)
Answer: (a) Only molecules with three or more atomscan follow the Lindemann-Hinshelwood mechanism
Q146. In the NMR spectrum, multiplicity of the signal (bold and underlined H atom) in the following species is [HNi(OPEt)]+ (I) 34 (II) PhSi(Me)H 2 (III) PH 3 (IV) (Cp*)ZrH(Cp*=pentamethylcyclopentadienyl) 2 2
Answer: (a) I-pentet, II-quartet, III-doublet and IV-singlet
Q147. The wave function for Be3+ in a certain state is 4 – r a given by ψ=Ne 0 , where N is the normalization constant, r is the distance of electron from the nucleus and a is the Bohr 0 radius. The most probable distance of the electron from the nucleus in this state is a
Answer: (a) 4a
Q148. Match the following Column I Column II (P) Associated Legendre (I) Harmonic Polynomials oscillator (Q) Hermite Polynomials (II) Particle in a box (R) Associated Laguerre model Polynomials (III) Angular part of (S) Trigonometric (IV) Radial part of Functions H atom H atom
Answer: (a) P→ III, Q →I, R → IV, S → II
