Astudent has two substances at a lab table. one substance is iron pyrite (fool's gold) and the other is real gold. after placing a 20.0-gram sample of iron pyrite into 40.0 ml of water in a graduated cylinder, it displaces 4.0 ml of water. the density of real gold is almost 4 times larger than iron pyrite. if a 20.0-gram sample of real gold is placed into the same amount of water, approximately how much water will be displaced?

the answer is true. hope it .

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