GATE CY format:nat PYQs & Answers — Page 14 — Exam Papers

Questions 131–140 of 166. Imported answers require independent review unless marked reviewed.

Topic practice 166 questionsPage 14 of 17

For the radioactive isotope ¹³¹I, the time required for 50% disintegration is 8 days. The time required for the 99.9% disintegration of 5.5 g of ¹³¹I is ________ days. (Up to one decimal place)

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Two moles of an ideal gas X and two moles of an ideal gas Y, initially at the same temperature and pressure, are mixed under isothermal-isobaric condition. The entropy change on mixing is __________ J K⁻¹. (Up to one decimal place. Use R = 8.31 J K⁻¹ mol⁻¹)

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The energy of a hydrogen molecule in its ground state equilibrium configuration is −31.7 eV. Its dissociation energy is _________ eV. (Up to one decimal place)

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The total number of valence electrons in W(η³-Cp)(η⁵-Cp)(CO)₂ is _____. (Atomic number of W = 74)

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In the ¹H NMR spectrum of an organic compound recorded on a 300 MHz instrument, a proton resonates as a quartet at δ 4.20 ppm. The individual signals of the quartet appear at δ 4.17, 4.19, 4.21 and 4.23 ppm. The coupling constant J in Hz is _____.

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In the electron ionization (EI) mass spectra, methyl hexanoate, methyl heptanoate and methyl octanoate give the same base peak. The m/z value of the base peak is _____.

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The rate constant of a first order reaction, X → Y, is 1.6 × 10⁻³ s⁻¹ at 300 K. Given that the activation energy of the reaction is 28 kJ mol⁻¹ and assuming Arrhenius behavior for the temperature dependence, the total time required to obtain 90% of Y at 350 K is__________ s. (Up to one decimal place. Use R = 8.31 J K⁻¹ mol⁻¹)

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The molar conductivity of a 0.01 M weak acid (HX) at 298 K, measured in a conductivity cell with cell constant of 0.4 cm⁻¹, is 64 S cm² mol⁻¹. The limiting molar conductivities at infinite dilution of H⁺ and X⁻ at 298 K are 350 and 410 S cm² mol⁻¹, respectively. Ignoring activity coefficients, the pKₐ of HX at 298 K is __________. (Up to two decimal places)

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The Latimer diagram of oxygen is given below. The value of x is ______ V. (Up to two decimal places)

Diagram for Chemistry question 45

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At temperature T, the canonical partition function of a harmonic oscillator with fundamental frequency (ν) is given by

For

, the probability of finding the harmonic oscillator in its ground vibrational state is ________. (Up to two decimal places)

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