Electrochemistry - Result Question 47

####49. On the basis of the information available from the reaction

43Al+O223Al2O3,ΔG=827kJmol1 of O2. The minimum e.m.f required to carry out an electrolysis of Al2O3 is (F=96500Cmol1)

(a) 8.56V

(b) 2.14V

(c) 4.28V

(d) 6.42V

[2003]

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Solution:

  1. (b) ΔG=nEF,AlAl3++3e

For 1mol of Al,n=3

for 43mol of Al,n=3×43=4

According to question,

827×1000=4×E×96500

E=827×10004×96500=2.14V



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