On the axes provided, label pressure on the horizontal axis from 0 mb to 760 mb and volume on the vertical from 0 to 1 ml. assign values to axes divisions in such a way that you occupy almost all the space on both axes. now locate and label the points: (90, 0.9), (100, 0.8), (400, 0.2), (600, 0.15), (760, 0.1)

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2