Question

Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g) If you have 4 moles of zinc and 4 moles of hydrochloric acid, which of these would be the limiting reactant? A) zinc B) hydrogen gas C) zinc chloride D) hydrochloric acid

Answer 1

D) hydrochloric acid.

Step-by-step explanation:

• The balanced equation for the mentioned reaction is:

Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g),

It is clear that 1.0 moles of Zn react with 2.0 moles of HCl to produce 1.0 moles of ZnCl₂ and 1.0 mole of H₂.

• From stichiometry; Zn reacts with HCl with (1: 2) molar ratio.

∴ 2.0 mol of Zn (the remaining 2.0 mol is in excess) react completely with 4.0 mol of HCl with (1: 2) molar ratio.

So,

the limiting reactant is HCl and the excess reactant is Zn.

Thus, the right choice is: D) hydrochloric acid.