Q.
14.96g of a mixture containing n-hexane and ethyl alcohol are reacted with sodium metal to give 200ml of H2 at 27∘C and 760mm pressure. The percentage of ethyl alcohol in the mixture is ______. [R=0.082Latmmol−1K−1]
1156
163
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Answer: 5
Solution:
Only ethyl alcohol reacts with sodium metal. C2H5OH+Na→C2H5ONa+1/2H2
No. of moles of H2 formed =RTPV =760760×1000200×0.082×3001 =15×8.21−1231−8.13×10−3 0.5 mole of H2 is liberated by 1 mole of C2H5OH. 8.13×10−3 mole H2 is liberated by 0.51×8.13×10−3 mole of C2H5OH =16.26×10−3 mole of C2H3OH =16.26×10−3×46g of C2H5OH =0.748g
The percentage of ethyl alcohol n the mixture =14.967.48×100=14.9674.8=5%