HCl has versatile applications starting from everyday life to laboratory uses and Ca is an alkaline earth metal. Let us try to bring some light on the reaction between HCl and Ca.
Ca is a reactive metal and HCl is a strong inorganic acid. The reaction between a strong acid and a reactive metal should be done cautiously. The reaction generates a salt and a gas.
As we move along this article, all important information about the reaction between HCl and Ca will emerge to us.
What is the product of HCl and Ca?
The products of the reaction HCl + Ca are calcium chloride (CaCl2) and hydrogen (H2) gas. We can write the equation for the reaction between Ca and HCl as shown below.
HCl (aq) + Ca (s) = CaCl2 (aq) + H2 (g)
What type of reaction is HCl + Ca?
HCl + Ca falls under the category of substitution or single displacement reaction as Ca atom displaces chloride ion (Cl-) from HCl molecule, forming CaCl2.
How to balance HCl + Ca
The equation for the reaction HCl + Ca without balancing looks as follows.
HCl + Ca = CaCl2 + H2
The following points should be kept in mind in order to get the balanced equation for the same reaction.
- The number of Ca atom is same on both the sides,
that is, HCl + Ca = CaCl2 + H2 - However, the number of H and Cl atoms, on both the sides is 1 and 2 respectively,
that is, HCl + Ca = CaCl2 + H2 - It is required to multiply HCl with 2 so that the number of H and Cl atoms are same on both the sides.
- The balanced equation for the reaction between Ca and HCl is as follows.
2HCl + Ca = CaCl2 + H2
HCl + Ca titration
HCl is an acid, but the other reactant, calcium is a metal. So, in this case, acid-base titration will be impossible.
HCl + Ca net ionic equation
The net ionic equation for the reaction between Ca and HCl is shown below.
2H+ (aq) + Ca (s) = Ca2+ (aq) + H2 (g)
To get the net ionic equation, the following steps should be followed.
- We can write dissociated cations and anions only for soluble ionic compounds. HCl, and CaCl2 being ionic, can dissociate.
- The complete ionic equation is as follows:
2H+ (aq) + 2Cl− (aq) + Ca (s) = Ca2+ (aq) + 2Cl− (aq) + H2 (g) - Only the chloride ion is the spectator ion here, the cancellation of which will result in the net ionic equation.
HCl + Ca conjugate pairs
In the reaction HCl + Ca,
- The conjugate pair for Ca is impossible as it is an element.
- Chloride ion (Cl–) is the conjugate base of the molecule HCl.
HCl + Ca intermolecular forces
- Though two different types of intermolecular forces (dipole-dipole, London dispersion) are present in HCl molecule, only dipole-dipole interaction predominates because of its polar nature.
- In Ca metal, no significant intermolecular forces are present as it is an element.
- CaCl2 being ionic in nature, can have electrostatic force of attraction.
HCl + Ca reaction enthalpy
The reaction enthalpy value for HCl + Ca is -542.7 kJ/mol. It is calculated as follows.
| Compounds | Enthalpy of formation (kJ/mole) |
|---|---|
| HCl (aq) | -167.2 |
| Ca (s) | 0 |
| CaCl2 (aq) | -877.1 |
| H2 (g) | 0 |
Reaction Enthalpy = Enthalpies of formation of [CaCl2 (aq) + H2 (g)] – Enthalpies of formation of [HCl (aq) + Ca (s)] = [(-877.1) + 0] – [2*(-167.2) + 0] = -542.7 KJ/mol.
Is HCl + Ca a buffer solution?
HCl + Ca cannot make a buffer solution as a weak acid or a weak base and its corresponding conjugate pair must be in a buffer solution. HCl is a strong acid.
Is HCl + Ca a complete reaction?
HCl + Ca will produce products by complete reaction; once the products are formed, reactant regeneration is impossible.
Is HCl + Ca an exothermic or endothermic reaction?
The reaction, HCl + Ca is exothermic in nature as heat is released.
Is HCl + Ca a redox reaction?
HCl + Ca is a redox reaction as the oxidation state of Ca is changed from 0 to +2, and that of H is changed from +1 to 0.
HCl + Ca redox reaction
Is HCl + Ca a precipitation reaction?
HCl + Ca is not a precipitation reaction as the product BaCl2 is a water-soluble solid, CO2 is a gas, and H2O is liquid.
Is HCl + Ca reversible or irreversible reaction?
HCl + Ca is an irreversible reaction as the reaction is unidirectional, that is, from left to right.
Is HCl + Ca a displacement reaction?
HCl + Ca is a displacement reaction as chloride ion (Cl–) is interchanged between HCl and Ca.
Conclusion
In conclusion, when hydrochloric acid reacts with the alkaline earth metal calcium, the products are CaCl2 and H2. CaCl2 is a water-soluble white solid, and H2 is a colorless, odorless gas. While doing the reaction, large pieces of Ca should be avoided as H2 being inflammable, may be ignited.
Hello, I am Tuluma Das, Completed my Ph.D. in Organic Chemistry from the Indian Association for the Cultivation of Science. I have a total of 9 years of research experience including a Ph.D. and Postdoc and 3 years of teaching experience. I have published 7 papers so far in international journals. Let’s connect through Linkedin :
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