Molalitas larutan NaCl 10% massa dalam air adalah... m. (Mr NaCl = 58,5)

10% NaCl = massa NaCl = 10 gram, massa air = 100 - 10 = 90 gram

m = (massa terlarut /Mr terlarut)* (1000/massa pelarut)
= (10/58,5)*(1000/90)
= 1,89 molal