Calculate the volume of the solution with a mass fraction of potassium hydroxide of 44% and a density of 1.46 g / ml

Calculate the volume of the solution with a mass fraction of potassium hydroxide of 44% and a density of 1.46 g / ml for dissolving aluminum weighing 8.1 g. What volume of hydrogen (n.o.)

Decision:
The reaction equation has the form;
2Al + 2KOH + 6H2O = 2K [Al (OH) 4] + 3H2 ↑
We find the mass of KOH spent on dissolving aluminum from the proportion, we get:
8.1g: xg = (2.27): (2.26);
x = [(2. 56). 8.1] / (2.27) = 16.8g.
Find the mass of the solution, we get:
m (p-pa) = [m (KOH). 100%] / 44% = (18.6 g. 100%) / 44% = 38.18 g.
Find the volume of the KOH solution, we get:
V (KOH) = m (p-pa) / p (p-pa) = 38.18 / 1.46 = 26.15 ml.
We find the amount of hydrogen that is released during the reaction from the proportion, we get:
8.1 g g: y l = (2.27) g: (3.22.4) l;
y = [8.1g. (3 .22.4) L] / (2.27) g = 10.8L.
Answer: V (KOH) = 26.15 ml; V (H2) = 10.8 l.