Question

39 gm of an alloy of aluminum and magnesium when heated with excess of dil. HCI from magnesium chloride, aluminum chloride, and hydrogen. the evolved hydrogen collected at 0C has a volume of 44.8 liters at 1atm pressures. Calculate the composition of the alloy by moles.
Solution

let the mole of magnesium be ( x ) and mole of aluminium be
( mathrm{y} ) ( mathrm{Mg}+2 mathrm{Hcl}--mathrm{MgCL} 2+mathrm{H} 2 )
( mathrm{Al}+3 mathrm{Hcl}-mathrm{m} / mathrm{Cl} 3+1.5 mathrm{H} 2 )
NOW
( 24 x+27 y=39 )
( x+1.5 y=2 )
solving these two equation we get ( x=.5, y=1 )
percentage of magnesium=30.76%
percentage of lauminium=69.24 %