Question

Zinc + Hydrochloric Acid → Zinc Chloride and Hydrogen Gas


Zn + 2HCl → ZnCl2 + H2

Explain why it is necessary to place a "2" in front of HCl in the reactants in the chemical equation. Use "evidence" and "scientific" reasoning to support your answer.

Answer 1

Answer:

This is because you need the same amount of atoms on each side and when you go to the reaction side you see that by adding the coefficient in from the H, 2, the hydrogen and chlorine react to make HCI :))

Answer 2

It is necessary to place 2 in the given reaction to balance the equation from both side.  

How to balance an equation?

A balanced equation has the equal number of atoms on the both side oh the equation.

In the given reaction:

$\bold{Zn + 2HCl = ZnCl_2 + H_2}$

Zinc is reacting with hydrochloric acid and making zinc chloride and hydrogen gas.

In the equation, there are two atoms of hydrogen and chloride in the product side and one atom of zinc.

If we do not put 2 on the reactant side, then there will be one atom of hydrochloric acid, which disbalance the equation.

Thus, we put 2 in the reactant side to balance the number of hydrogen in both side.

Learn more about, balanced equation, here:

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