Home › WAEC WASSCE › Chemistry › Stoichiometry of Chemical Reactions › Combining 3 mol of H2 with 2 mol of Cl2 for H2 +…
Combining 3 mol of H2 with 2 mol of Cl2 for H2 + Cl2 giving 2HCl, which reactant limits the product?
AHydrogen, since more of it is present
BChlorine, since less of it is present
CNeither, since the ratio is already 1 to 1
DBoth equally, since each gives 2 mol HCl
Answer & Solution
Correct answer: B. Chlorine, since less of it is present
1. The balanced equation needs hydrogen and chlorine in a 1 to 1 mole ratio.
2. The mixture supplies 3 mol to 2 mol, a ratio of 1.5 to 1, which is richer in hydrogen.
3. Complete reaction of 3 mol H2 would give 6 mol HCl.
4. Complete reaction of 2 mol Cl2 would give only 4 mol HCl.
5. The smaller figure is the real yield, so chlorine limits and hydrogen is in excess.
6. Reacting all 2 mol Cl2 uses 2 mol of the 3 mol H2, leaving 1 mol H2 unreacted.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 4 "Stoichiometry of Chemical Reactions", section 4.4 Reaction Yields_
Related questions
In the reaction between sodium and chlorine, sodium is oxidised, which means chlorine:Ordering the three ways of writing a reaction from most to least detail about ions gives:When one element appears in more than one formula on the same side of an equation, you musWhen balancing a combustion equation, an odd number of oxygen atoms on the product side isCompounds that produce hydroxide ions by chemically reacting with water, rather than by diA double arrow is used in an acid equation to indicate that the acid is:A neutralisation reaction has an acid and a base as reactants and typically produces:Sodium hydroxide is classified as a strong base because in water it: