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JEE Main 201912 AprilMorning Shift
Exam
JEE Main
Year
2019
Date
12 April
Shift
Morning Shift
Subject
Chemistry
Chapter
Thermodynamics (C)

JEE Main 2019 · 12 April · Morning Shift · Chemistry · Thermodynamics (C)

Enthalpy of sublimation of iodine is 24cal g ^ - 1 at 200 ° C . If...

Enthalpy of sublimation of iodine is 24calg−124cal{g}^{- 1} at 200°C200 ° C . If specific heat of I2{I}_{2} (s)andI2and {I}_{2} (vap) are 0.0550.055 and 0.031calg−1K−10.031cal{g}^{- 1}{K}^{- 1} respectively, then enthalpy of sublimation of iodine at 250°C250 ° C in calg−1cal{g}^{- 1} is:

Options

  1. A11.411.4
  2. B2.852.85
  3. C22.822.8
  4. D5.75.7

Correct answer

C. 22.822.8

Step-by-step solution

I2(s)→I2(g){I}_{2}\left(s\right) \to {I}_{2}\left(g\right)
(\DeltaH)250oC−(\DeltaH)200oC=ΔCpm(T2−T1){\left(\DeltaH\right)}_{{250}^{o}C} - {\left(\DeltaH\right)}_{{200}^{o}C} = \Delta{C}_{pm}\left({T}_{2} - {T}_{1}\right)
(\DeltaH)250oC−24=(0.013−0.055)×50{\left(\DeltaH\right)}_{{250}^{o}C} - 24 = \left(0.013 - 0.055\right) \times 50
(\DeltaH)250oC−24=−1.2{\left(\DeltaH\right)}_{{250}^{o}C} - 24 = - 1.2
(\DeltaH)250oC=22.8J/gm{( \DeltaH )}_{{250}^{o}C} = 22.8J / gm
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