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QJEEM19Chbd05: JEE Main 2019 Chemistry - Class 11 JEEM19Chbd05 Solution: Enthalpy of sublimation of iodine is 24 cal g –1 at 200 o C. If …

Enthalpy of sublimation of iodine is 24 cal g–1 at 200 oC. If specific heat of I2(s) and l2 (vap) are 0.055 and 0.031 cal g–1K –1 respectively, then enthalpy of sublimation of iodine at 250 oC in cal g–1 is :

Multiple Choice Options

  • A 2.85
  • B 22.8
  • C 11.4
  • D 5.7

Step-by-Step Verified Solution

Kirchoff's Equation :

ΔHT2−ΔHT1T2−T1=Δ(Cp)

Sublimation of iodine :

I2(s) → I2(g)

ΔH250∘C−ΔH200∘C250−200=Cp[I2(g)]−Cp[I2(s)]

ΔH250∘C−2450=(0.031−0.055)

⇒ ΔH250∘C = 22.8 cal g–1

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