jika 20 gram NaOH (mr=40 ) di larutkan kedalam 90 gram air (Mr=18), maka fraksi mol NaOH adalah?

wt = 20 gr (Mr = 40)
wp = 90 gr (Mr = 18)
Xt = .......................?

nt = wt/Mr = 20/40 = 0,5 mol
np = wp/Mr = 90/18 = 5 mol

Xt = nt/(nt+np) = 0,5/(0,5+5) = 0,5/5,5 = 0,091