Consider the following statements, and then rate them using the following scale: 1 = strongly agree 2 = undecided 3 = strongly disagree

a. Plastic goods are essential in our modern world:
b. Plastics do not harm the environment if we recycle them:
c. We need to invent more biodegradable plastics:
d. Plastic products are better than products made of glass, metal or paper because plastic costs less:
e. Chemicals fertilizers and pesticides endanger young children and animals:
f. Chemicals do not harm the soil, even if they are harmful to pests:

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