Question

Zinc (Zn) combines with hydrogen chloride (HCI) to form

hydrogen gas (H₂) and zinc chloride (ZnCl₂).
Which equation represents this chemical reaction?
A. ZnCl₂ + Zn
B. 2HCI
→
→
H₂ + Zn + ZnCl₂
OC. ZnH₂ + ZnCl₂ + 2HCI
H₂ + 2HCI i know the answer but why is it 2HCI where does the 2 come from?

Answer 1

Step-by-step explanation:

ZnCl
`_(2)` + H
`_(2)` ⇒ Zn + 2HCl

The two in 2HCl comes after balancing the equation.

The number of elements reacting should be equal to the number of products being formed.

The left side of the equation:

ZnCl
`_(2)` + H
`_(2)`

has;

1 Zn

2 Cl

and 2 H

while at the right side of the equation:

Zn + HCl

We have;

1 Zn

1 Cl

1 H

Therefore, in order to balance the equation we multiply 2 with both H and Cl.

1 x 2 = 2H

1x 2 = 2Cl

Thus we get;

Zn + 2HCl