The correct option is A 17.5%
% of N2 by Duma's method = 28×VN2×10022400×mass of organic compound
Now, calculating the vol of N2 at STP using ;
P1V1T1=P2V2T2
PN2×VN2T 270 C=PN2×VN2T 00 C−−−−−(1)
PN2=(Pmoist gas−aq.tension)
= 715 - 15 = 700 mm of Hg
putting the value of PN2 in equation (1)
700×50300=760×VN2273
VN2=7×50× 273760×3
∴% of N2= 28×41.91×10022400×0.3
=17.5 %