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Topic: Confusion in calculating limiting reactants  (Read 1885 times)

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Offline mariam amro

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Confusion in calculating limiting reactants
« on: September 18, 2015, 05:25:07 AM »
How many moles of hydrogen gas can be produced from the following reaction if 65 grams of zinc and 36.5 grams of HCL are present in the reaction?
Zn(s) +2HCL(aq) --> ZnCl2(aq)+ H2(g)
The answer choices are : A) 1 mole B) 1.8 mole C) 3.6 mole D) 7.0 mol E) 58

I know how to solve such questions but got an answer of 0.5 moles of hydrogen. When I checked the answer in my book it was 1 mole (A). My mistake was that I considered HCL as the limiting reactant not Zn.

Here is what I did to find the limiting reactant:
I found moles of both Zn and HCl... 1mole each
Now I divided the moles of each by their corresponding coefficients and compared the 2 . Zn... 1 while HCl ... 1/2
So I concluded that HCl is the limiting.

What is wrong with my method? Because this was the way I solved all limiting reactants problems and they are correct.

Thank you for your help.:)

Offline Borek

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Re: Confusion in calculating limiting reactants
« Reply #1 on: September 18, 2015, 05:27:53 AM »
Answers given are wrong. 0.5 moles of hydrogen is a correct answer, HCl is the limiting reagent and I see nothing wrong with your approach :)
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