GATE XL format:nat PYQs & Answers — Page 12 — Exam Papers

Questions 111–120 of 244. Imported answers require independent review unless marked reviewed.

Topic practice 244 questionsPage 12 of 25

The time taken by a first order reaction to reach 90% completion is 20 s. The time taken for the reaction to reach 50% completion is ______ s (rounded off to the closest integer).

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The ground state energy of an electron in a hydrogen atom is −13.60 eV. The energy of the electron in the third excited state is ______ eV (rounded off to two decimal places).

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A solution of a compound shows an absorbance of 0.42 at 275 nm in a cuvette with 0.1 dm light path. The molar absorptivity of the compound is

. The concentration of the compound is ______ × 10

M (rounded off to the closest integer).

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Given the following standard heats of formation,

,

, and

, the average bond enthalpy of a P–H bond in PH₃(g) is ________ kJ mol⁻¹ (rounded off to one decimal place).

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The total number of possible geometrical isomer(s) for [PtBrCl(NH₃)(py)]⁰ is ________. (Given: py = Pyridine and atomic number of Pt = 78)

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Given the standard reduction potentials,

and

, the potential of the following cell

at 25 °C is ________ V (rounded off to two decimal places). (Given: Faraday constant = 96500 C mol⁻¹, Gas constant R = 8.314 J K⁻¹ mol⁻¹)

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The freezing point of 80 g of acetic acid (freezing point constant 3.9 K kg mol⁻¹) was lowered by 7.8 K due to the addition of 20 g of a compound. The molar mass of the compound is ________ g mol⁻¹ (rounded off to closest integer).

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In spiral phyllotaxis, leaves are initiated sequentially on the meristem with two successive primordia being separated by golden angle. If a plant follows right-handed spiral phyllotaxis when looked down the meristem, then the angle between two successive leaves would be ________ degrees (with correct sign, round off to one decimal place).

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In a diploid plant species, the T allele produces tall individuals and is completely dominant over the t allele that produces short individuals. Similarly, the W allele produces round seeds and is completely dominant over the w allele that produces wrinkled seeds (assume T and W loci are not linked). If a parent with TTWW genotype is crossed to another parent with ttww genotype, the fraction of the F₂ population produced by the fusion of both recombinant gametes would be ________. (Round-off to two decimal places.)

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In a population of a diploid plant species obeying Hardy-Weinberg equilibrium, a locus regulating flower color has two alleles R and r. Individuals with RR, Rr and rr genotypes produce red, pink and white flowers, respectively. If the ratio of red, pink and white flower-producing individuals in the population is 6:3:1, then the frequency of r allele in the population would be ______%. (Round-off to two decimal places.)

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