Zinc carbonate and Hydrochloric acid Reaction | ZnCO3 + HCl
Zinc carbonate (ZnCO3) reacts with aqueous hydrochloric acid (HCl) and emit carbon dioxide gas (CO2) and give Zinc chloride (ZnCl2) and water (H2O) as products. Zinc carbonate is a white precipitate and when reaction happens, precipitate is dissolved and a colourless aqueous solution is given.
In this tutorial, we will discuss followings.
Balanced reaction of ZnCO3 and HCl
ZnCO3(s) + 2HCl(aq) → ZnCl2(aq) + CO2(g) + H2O(l)
One mole of ZnCO3 reacts with two moles of HCl. As products, one mole of ZnCl2, one mole of CO2 and one mole of H2O are given.
Reactants of reaction
Zinc carbonate
Zinc carbonate is a white precipitate and not soluble in water. So, you may see a white solid is being deposited in water when zinc carbonate is added to water.
Hydrochloric acid
Hydrochloric acid is a strong acid because it readily dissociates to H+ and Cl- ions in water. These Hydrochloric acid solutions should show pH values much lower than 7 due to its strong acidic nature.
Products of reaction
Zinc chloride (ZnCl2)
Zinc chloride is a salt and soluble in water to form a colourless aqueous solution.
Change of oxidation numbers
This reaction is not a redox reaction because oxidation numbers of atoms are not changed during the reaction.
- Zinc's only oxidation state is +2. In both ZnCO3 and ZnCl2, Zinc's is at +2 oxidation state.
- Chlorine's oxidation number in HCl is -1. And also, on ZnCl2, oxidation number of chlorine is -1.
Physical and chemical observation of ZnCO3 and HCl reaction
Here, we will see some physical observations and chemical properties changes during the reaction. These observations are important to identify compounds from other compounds in the qualitative analysis.
"Colour and physical state changes
- As mentioned earlier, zinc carbonate (ZnCO3) is not soluble in water and exist as a white precipitate. Aqueous hydrochloric acid (HCl) is a colourless solutions.
- Zinc chloride is soluble in water and give colourless solution. Carbon dioxide is a gas at room temperature and poorly soluble in water.
pH change
- Reactants: Though ZnCO3 is not soluble in water, due to presence of very low soluble carbonate ion amount in water, pH value will be just over 7. But HCl is strong acid and should show pH value less than 7.
- Products: Zinc chloride is a salt. Both Zn2+ and Cl- ions are stable in water and do not participating in hydrolysis. Though all HCl and ZnCO3 are completely reacted with each other, due to presence of CO2 gas molecules in water, Carbonic acid (H2CO3) acid can formed in minor quantities. In such cases, pH of final solution should be less than seven.
Safety, health hazards and environmental impacts due to ZnCO3, HCl, ZnCl2
- HCl: You should be extremely careful when diluted HCl solution is prepared by concentrated HCl becauase HCl vapour can harm eyes and skin. Also, it is toxic if inhaled. Serious skin burns are possible.
- ZnCO3: Very toxic to aquatic life.
- ZnCl2: Harmful if swallowed, can causes severe skin burns and eye damage and Very toxic to aquatic life
Have Questions?
What will happen when very less quantity of Hydrochloric acid (HCl) is added to Zinc carbonate (ZnCO3). Assume that ZnCO3 exist as a precipitate in an aqueous solution.
If added HCl quantity is not enough to react with all available ZnCO3, there is a possibility of presence of white precipiate (ZnCO3) furthermore. This depends on the remaining ZnCO3 quantity and Ksp value of ZnCO3. You have to use Ksp expression in such cases.
What is the ZnCO3 + HCl type of reaction?
ZnCO3 is a metal carbonate. When metal carbonate reacts with dilute strong acid such as HCl, Carbon dioxide gas molecules are generated as a result.