Question

According to the law of conservation of mass, what should the product side of this single replacement reaction look like? A. H2 ZnCl2 B. H2 + Zn + Cl2 C. H2 + ZnCl2 D. ZnCl2

Answer 1

Answer: The product side must be $ZnCl_2+H_2$

Explanation:

Single displacement reaction is defined as the reaction in which more reactive metal displaces a less reactive metal from its chemical reaction.

$AB+C\rightarrow CB+A$

Metal C is more reactive than metal A.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form. This also means that total number of individual atoms on reactant side must be equal to the total number of individual atoms on the product side.

When zinc metal reacts with hydrochloric acid, it leads to the production of zinc chloride and hydrogen gas. The chemical reaction follows:

$Zn+2HCl\rightarrow ZnCl_2+H_2$

On reactant side:

Number of zinc atoms = 1

Number of hydrogen atoms = 2

Number of chlorine atoms = 2

On product side:

Number of zinc atoms = 1

Number of hydrogen atoms = 2

Number of chlorine atoms = 2

Hence, the product side must be $ZnCl_2+H_2$