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Classification Of Elements And Periodicity In Properties

Question
CBSEENCH11005527

The electron gain enthalpy of chlorine is 3.7 eV per atom. How much enthalpy in kJ is released when 1g of chlorine is converted completely of Cl- ion in the gaseous state?

Solution

We know,
 Cl left parenthesis straight g right parenthesis plus space straight e to the power of minus space space space rightwards arrow space space Cl to the power of minus left parenthesis straight g right parenthesis space plus space 3.7 space eV
Now space 1 eV space equals space 96.3 space kJ space mol to the power of negative 1 end exponent
therefore space space space space 3.7 space eV space equals space 96.3 space cross times space 3.7 space eV space mol to the power of negative 1 end exponent
space space space space space space space space space space space space space space space space space equals space 357.05 space kJ space mol to the power of negative 1 end exponent
because space enthalpy space released space when space 35.5 space straight g space left parenthesis 1 space mole right parenthesis comma
space space space space of space chlorine space is space completely space
converted space to space Cl to the power of minus space left parenthesis straight g right parenthesis space ions space space equals space 357.05 space kJ
space space space therefore space space space enthalpy space released space when space 1 straight g space of space chlorine space is comma
space completely space converted space to space Cl to the power of minus left parenthesis straight g right parenthesis space ions
space space space space space equals fraction numerator 357.05 over denominator 35.5 end fraction space equals 10.04 space kJ