Boiling point of water at 750mm of hg is 99.63°C. how much sucrose is to be added to 500g of water such that it boils at 100°C.​​​​​​​

Asked by goyalpavitarta | 3rd May, 2021, 01:25: PM

Expert Answer:

Molal elevation constant for water is 0.52 K Kg mol-1.
 
E l e v a i o n space o f space b o i l i n g space p o i n t left parenthesis increment T subscript b right parenthesis equals left parenthesis 100 plus 273 right parenthesis minus left parenthesis 99.63 plus 273 right parenthesis
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals 0.37 space K

M a s s space o f space w a t e r left parenthesis w subscript 1 right parenthesis equals 500 space g
M o l a r space m a s s space o f space s u c r o s e space left parenthesis C subscript 12 H subscript 22 O subscript 11 right parenthesis equals 11 cross times 12 plus 22 cross times 1 plus 11 cross times 16 equals 342 space g space m o l to the power of negative 1 end exponent

increment straight T subscript straight b equals fraction numerator straight K subscript straight b cross times 1000 cross times straight w subscript 2 over denominator straight M subscript 2 cross times straight w subscript 1 end fraction
straight w subscript 2 equals fraction numerator increment straight T subscript straight b cross times straight M subscript 2 cross times straight w subscript 1 over denominator straight K subscript straight b cross times 1000 end fraction
straight w subscript 2 equals fraction numerator 0.37 cross times 342 cross times 500 over denominator 0.52 cross times 1000 end fraction

straight w subscript 2 equals 121.67 space straight g space of space sucrose space is space to space be space added.

Answered by Ravi | 3rd May, 2021, 04:34: PM