Hydrogen Iodide and Calcium Hydroxide are inorganic compounds with chemical formulas, HI and Ca(OH)2, respectively. Let us explore more about the reaction between HI and Ca(OH)2.
Ca(OH)2, commonly known as slaked lime, is a colorless crystal or white amorphous solid. HI is a colorless, corrosive oily liquid. Ca(OH)2 interacts with acids easily due to its basic nature.
In this article, we will learn about a few properties based on the reaction HI + Ca(OH)2, like the type of reaction, the product formed, buffer solution, conjugate pairs etc.
What is the product of HI and Ca(OH)2?
Calcium Iodide (CaI2) and Water (H2O) are formed when HI reacts with Ca(OH)2.
Ca(OH)2 + HI → CaI2 + H2O
What type of reaction is HI + Ca(OH)2?
HI + Ca(OH)2 is classified as an acid-base reaction, also a neutralization reaction where a strong base to produce salt and water.
How to balance HI + Ca(OH)2?
The equation for the reaction between HI + Ca(OH)2 is balanced using the following steps.
Ca(OH)2 (s) + HI (l) → CaI2 (s) + H2O (l)
- Calculate the number of moles of each element involved in both the reactant and product side of the reaction.
| Elements | Reactant side | Product side |
|---|---|---|
| Ca | 1 | 1 |
| O | 2 | 1 |
| H | 3 | 2 |
| I | 1 | 2 |
- The number of I atoms can be balanced by adding 2 to HI on the reactant side.
- To balance H atoms on the product side we add 2 to H2O on the product side.
- Thus, the overall balanced reaction is given by-
- Ca(OH)2 + 2HI → CaI2 + 2H2O
HI + Ca(OH)2 titration
HI + Ca(OH)2 titration is not possible because HI being a very strong acid will neutralize Ca(OH)2 as soon as it is formed, identification of any end point will not be possible with use of indicators.
HI + Ca(OH)2 net ionic equation
The net ionic equation between Ca(OH)2 + HI is –
Ca2+ + OH– + H+ + I– = CaI2 + H2O
The following steps are followed to derive the net ionic equation:
- Write the balanced molecular equation along with the physical state.
- Ca(OH)2 + 2HI →CaI2 + 2H2O
- Now, write the ionic form of each of the substances existing in aqueous form and capable of dissociating completely in water. HI is a weak acid that does not completely dissociate into ions in aqueous form. Hence, the complete ionic equation is –
- Ca2+ + OH– + H+ + I– = CaI2 + H2O
- We find that the complete ionic equation is identical to the net ionic equation.
- Ca2+ + OH– + H+ + I– = CaI2 + H2O
HI + Ca(OH)2 conjugate pairs
The conjugate pairs of HI and Ca(OH)2 are as follows:
- I– is the conjugate base of HI.
- Conjugate acid of Ca(OH)2 is Ca2+.
HI + Ca(OH)2 intermolecular forces
The intermolecular forces of HI and Ca(OH)2 are as follows:
- Dipole-dipole interactions and well as dispersion forces are observed in HI. This is because HI is a polar molecule.
- For Ca(OH)2, the major intermolecular force is the ionic bond between the calcium and hydroxyl ions.
HI + Ca(OH)2 reaction enthalpy
The enthalpy of reaction for HI + Ca(OH)2 is –15.26 kcal/ mol.
Is HI + Ca(OH)2 a buffer solution?
HI + Ca(OH)2 is a buffer solution. It is an indirect acidic buffer solution, as the reaction constitutes a weak acid and calcium iodide salt, formed from a weak acid and a strong base.
Is HI + Ca(OH)2 a complete reaction?
HI + Ca(OH)2 is a complete reaction, as HI, a strong acid, dissociates completely in solution.
Is HI + Ca(OH)2 an exothermic or endothermic reaction?
HI + Ca(OH)2 is an exothermic reaction as the reaction enthalpy is negative.
Is HI + Ca(OH)2 a redox reaction?
The reaction between HI + Ca(OH)2 is not redox reaction, as both of the reactants do not undergo a change in their oxidation state upon reaction.
Is HI + Ca(OH)2 a precipitation reaction?
The reaction HI + Ca(OH)2 is an example of an precipitation reaction, where insoluble CaI2 is formed as the product.
Is HI + Ca(OH)2 an irreversible reaction?
HI + Ca(OH)2 is an irreversible reaction because the calcium iodide and water cannot go back to their reactant state spontaneously.
Is HI + Ca(OH)2 a displacement reaction?
The reaction HI + Ca(OH)2 is a displacement reaction because the the anions and cations of the two reactants have interchanged to form the respective products.
Conclusion
Hydrogen Peroxide and Calcium Hydroxide react to yield Calcium Iodide as a product. This reaction is a very popular displacement reaction. Also, CaI2 is used in photography now.
Hi, I am Aparajita Bose. I am a Chemistry postgraduate currently working with Micro Labs Advanced Research Centre as a Research Associate. I am passionate about my subject and am excited to educate my readers with precise knowledge. I also want to make the subject fun and easily accessible!
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