Hidroxidul are formula: MeOH
%H = m H/ m MeOH * 100
2,5 = 1/(x+17) * 100 => 100x = 2,5x + 42.5
=> 2,5x = 57.5 => x = 23
Metalul cu A = 23 este sodiul => hidroxidul: NaOH
40 g NaOH...........16 g O
32 g NaOH..........x g O
x = 12.8 g O
masa oxigen = 5 * 12.8= 64 g
18 g apa..........16 g O
x g apa.............64 g O
x = 72 g apa
md = 32 g
ms = md + m apa = 72 + 32 = 104 g solutie
c = md/ms * 100 = 32/104 * 100 = 30.76 %
n solvat = m NaOH/masa molara NaOH = 32/40 = 0.8 moli
n solvent = m apa/masa molara apa = 74/18 = 4 moli
n solvat/n solvent = 0.8/4 = 0,2/1
