B
Acid rain is a dilute solution of acids that dissolve
the calcium carbonate in limestone statues.
Concentrated acids can dissolve a large piece of
limestone in a few days. Statue breakdown due to
acid rain can take decades, but statues with
intricate carvings break down more quickly.
Explain these observations in terms of reaction
rates.

i believe the answer is a.

the maximum mass of nh3 is nh3 in grams

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