Question

__Zn + __HCl --> __ZnCl2 + __H2

If 26.22 Liters of Hydrogen gas are produced, how many moles of Hydrochloric acid were reacted?

Answer 1

1. The balanced equation:

Zn + 2HCl —> ZnCl₂ + H₂

The coefficients are: 1, 2, 1, 1

2. 2.34 moles of HCl

Step-by-step explanation:

1. The balanced equation

__Zn + __HCl —> __ZnCl₂ + __H₂

There are 2 atoms of H on the right side and 1 atom on the left side

It can be balance by writing 2 before HCl as shown below:

Zn + 2HCl —> ZnCl₂ + H₂

Now the equation is balanced.

The coefficients are: 1, 2, 1, 1

2. Determination of the number of mole of HCl that reacted.

NOTE: 1 mole of H₂ = 22.4 L at STP.

Zn + 2HCl —> ZnCl₂ + H₂

From the balanced equation above,

2 moles of HCl reacted to produce 1 mole (i.e 22.4 L) of H₂.

Finally, we shall determine the number of mole of HCl needed to produce 26.22 L of H₂. This can be obtained as follow:

From the balanced equation above,

2 moles of HCl reacted to produce 22.4 L of H₂.

Therefore, Xmol of HCl will react to produce 26.22 L of H₂ i.e

Xmol of HCl = (2 × 26.22)/22.4

Xmol of HCl = 2.34 moles

Thus, 2.34 moles of HCl is needed for the reaction.