Which of the following is the correct ionization equation for calcium iodide in water?

A. [tex]$CaI_2 (s) \xrightarrow{H_2O} Ca^{2+}(aq) + 2 I^{-}(aq)$[/tex]
B. [tex]$CaI_2 (s) \xrightarrow{H_2O} Ca^{2+}(aq) + I_2^{2-}(aq)$[/tex]
C. [tex]$CaI_2 (s) + 2 H_2O (l) \rightarrow Ca(OH)_2 (aq) + 2 HI (aq)$[/tex]
D. [tex]$CaI_2 (s) \xrightarrow{H_2O} Ca^{+}(aq) + I_2^{-}(aq)$[/tex]



Answer :

To determine the correct ionization equation for calcium iodide (CaI₂) in water, let's go through each option and analyze the chemical reactions:

1. Option A:
[tex]\[ CaI_2(s) \xrightarrow{H_2O} Ca^{2+}(aq) + 2 I^{-}(aq) \][/tex]

In this option, solid calcium iodide dissociates into calcium ions and iodide ions when dissolved in water. This is a typical ionic dissociation process for an ionic compound like CaI₂.

2. Option B:
[tex]\[ CaI_2(s) \xrightarrow{H_2O} Ca^{2+}(aq) + I_2^{2-}(aq) \][/tex]

This option suggests that calcium iodide dissociates into calcium ions and an unusual ion, I₂²⁻, which is not a common ion produced from dissociation in water. This would be a highly unlikely ionization equation.

3. Option C:
[tex]\[ CaI_2(s) + 2 H_2O(l) \rightarrow Ca(OH)_2(aq) + 2 HI(aq) \][/tex]

This option represents a chemical reaction involving water and produces calcium hydroxide and hydroiodic acid. However, this is not an ionization equation but rather a chemical reaction that leads to different products, not the simple dissociation of CaI₂ in water.

4. Option D:
[tex]\[ CaI_2(s) \xrightarrow{H_2O} Ca^{+}(aq) + I_2^{-}(aq) \][/tex]

In this option, CaI₂ is suggested to dissociate into Ca⁺ and I₂⁻, which are incorrect charges for these ions. The common ions from CaI₂ dissociation would be Ca²⁺ and I⁻.

After reviewing all the options, the correct ionization equation for calcium iodide in water is given by Option A:

[tex]\[ CaI_2(s) \xrightarrow{H_2O} Ca^{2+}(aq) + 2 I^{-}(aq) \][/tex]

This equation correctly shows the dissociation of CaI₂ into its constituent ions in aqueous solution. Therefore, the correct answer is:

Option A.