Reaction equation:
Al(OH)₃ + 3HCl → AlCl₃ + 3H₂O
Moles of Al(OH)₃:
moles = mass/Mr
= 1.51 / (27 + 17 x 3)
= 0.019
Molar ratio Al(OH)₃ : HCl = 1 : 3
Moles of HCl required = 0.019 x 3
=0.057
concentration = moles/volume
volume = 0.057 / 0.1
= 0.57 dm³
= 570 ml
The answer you’re looking for is 0.250
All matter is made up of particles called atoms and molecules (as opposed to being continuous or just including particles). On the following page, the idea is stated as one of four concepts in Dalton's theory: “All matter is composed of tiny, indivisible particles called atoms” (p. 158s).