GATE CY Spectroscopy PYQs & Answers

Questions 1–10 of 52. Imported answers require independent review unless marked reviewed.

Among the following, the one for which the infrared active vibrational modes are Raman inactive and vice versa is

Your answerChoose one option.

H₂O

trans-planar conformer of H₂O₂

eclipsed conformer of ethane

CH₄

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In the ¹H NMR spectrum of compound X, the coupling constant (Jₐᵦ) between Hₐ and Hᵦ is 3 Hz. The amino alcohol(s) that give(s) X on reaction with methyl iodide followed by heating is(are)

Your answerSelect all correct options. You can choose more than one.

Diagram for Chemistry question 23 (figure 2)

Diagram for Chemistry question 23 (figure 3)

Diagram for Chemistry question 23 (figure 4)

Diagram for Chemistry question 23 (figure 5)

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A 0.005 M solution of compound X transmits 80% of the incident light of wavelength (λ) 500 nm. The absorbance of 0.01 M solution of X is _____ (rounded off to three decimal places).

(Given: path length = 1.0 cm)

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The microwave spectrum of gaseous HF consists of a series of lines separated by 41.11 cm

. The bond length (in Å) of HF is _____ (rounded off to two decimal places).

(Given: Atomic mass (in amu): H = 1.008, F = 18.998; 1 amu = 1.661 × 10

kg; h = 6.626 × 10

J s; c = 2.998 × 10

m s

)

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In a

H NMR spectrum obtained from a spectrometer operating at a magnetic field of 14.1 T, two resonances are observed at 1.25 ppm and 5.75 ppm. The separation between the two resonances (in Hz) is _____ (rounded off to one decimal place).

(Given: gyromagnetic ratio (γ) of H = 2.675 × 10

)

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The correct match for the protons labeled in compound X in Column M with the corresponding chemical shifts (δ, ppm) in Column N is

Column M: P—H

; Q—H

; R—H

; S—H

Column N: I—7.00 (dd, J = 8.4, 7.3, 1.4 Hz, 1H); II—7.17 (dd, J = 8.4, 1.4 Hz, 1H); III—7.59 (dd, J = 8.4, 7.3, 1.4 Hz, 1H); IV—8.12 (dd, J = 8.4, 1.4 Hz, 1H).

Your answerChoose one option.

P → II; Q → III; R → I; S → IV

P → I; Q → IV; R → II; S → III

P → II; Q → IV; R → I; S → III

P → I; Q → III; R → II; S → IV

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In the

H-NMR spectrum of the following molecule, the signal of proton Hₐ appears as

Your answerChoose one option.

singlet

triplet

quintet

quartet

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Rigid rotor wavefunctions are given by

. The wavefunctions

and

are given below

For a non-polar diatomic molecule, the value of transition dipole moment integral for transition between

and

is equal to

Your answerChoose one option.

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The Vaska’s complex trans-IrCl(CO)(PPh₃)₂ shows a band at 1967 cm⁻¹ for the νCO stretching vibration in its infrared spectrum. The complex(es) that will show an increase in the νCO stretching vibration from 1967 cm⁻¹ is/are

Your answerSelect all correct options. You can choose more than one.

Diagram for Chemistry question 21 (figure 2)

Diagram for Chemistry question 21 (figure 3)

Diagram for Chemistry question 21 (figure 4)

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The total number of hyperfine lines expected in the EPR spectrum of •CH

OH (radical) is ______ (in integer). [Note: Consider all hydrogen atoms for calculation]

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GATE CY Spectroscopy PYQs

How to practice Spectroscopy

Question 19

Question 23

Question 31

Question 32

Question 33

Question 37

Question 16

Question 19

Question 21

Question 31