Question

when 2.37g of magnesium reacts with 4.56g of hydrochloric acid 0.11g of hydrogen gas is produced. What is the percent yeild of this reaction

Answer 1

Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2

use this reaction to look for a limiting reagent

Mg

n=2.37/24.305=0.098 mol

use the ratio to find the number of moles for H2

1:1

0.098:x

no of moles for H2=0.098mol

use the same procedure

HCl

n=4.56/(1.0079+35.453)=0.125mol

H:HCl

1:2

x:0.125mol

H2 moles =0.0625mol

therefore HCl is a limiting reagent because it produces less number of moles

look fo H2 mass

m=nMr

m=(0.0625)(2.0158)=0.126g

percentage yield =0.11/0.126×100=87.31%