Which of the following is the correctly balanced equation for the complete neutralation of A by Ca(OH)2?
The Correct Answer and Explanation is :
To determine the correct balanced equation for the complete neutralization of an acid (let’s assume the acid is hydrochloric acid, HCl) by calcium hydroxide, Ca(OH)₂, we need to make sure that the products of the reaction are water (H₂O) and a salt, and that the number of atoms for each element is equal on both sides of the equation. The reaction involves the acid HCl and the base Ca(OH)₂.
The unbalanced chemical equation is:
[ \text{Ca(OH)}_2 + \text{HCl} \rightarrow \text{CaCl}_2 + \text{H}_2\text{O} ]
Balancing the Equation:
- Calcium hydroxide, Ca(OH)₂, dissociates into Ca²⁺ and 2OH⁻ in solution.
- Hydrochloric acid, HCl, dissociates into H⁺ and Cl⁻.
- To completely neutralize the hydroxide ions (OH⁻) from Ca(OH)₂, each OH⁻ needs a corresponding H⁺ ion from HCl. Since there are 2 OH⁻ ions in one formula unit of Ca(OH)₂, we need 2 H⁺ ions, meaning 2 HCl molecules are required for complete neutralization.
Thus, the balanced chemical equation is:
[ \text{Ca(OH)}_2 + 2\text{HCl} \rightarrow \text{CaCl}_2 + 2\text{H}_2\text{O} ]
Explanation:
- Stoichiometry: The reaction requires two moles of HCl for every mole of Ca(OH)₂. This stoichiometric balance ensures that all hydroxide ions from calcium hydroxide react with the hydrogen ions from hydrochloric acid to produce water.
- Product Formation: The calcium ion (Ca²⁺) from Ca(OH)₂ reacts with the chloride ions (Cl⁻) from HCl to form calcium chloride (CaCl₂), a salt.
- Conservation of Mass and Charge: The equation is balanced in terms of both mass and charge. Both sides of the equation have one Ca, two Cl, two H, and two O atoms, maintaining the law of conservation of mass. The charges are also balanced, with neutral species on both sides of the equation.
- Reaction Type: This is a classic example of an acid-base neutralization reaction, where an acid reacts with a base to produce water and a salt. Such reactions are exothermic, releasing heat.
Now, I’ll generate an image depicting this balanced chemical reaction.
Here is the visual representation of the chemical reaction between calcium hydroxide and hydrochloric acid. This image illustrates the reaction in a laboratory setting, showing the conversion of the reactants into calcium chloride and water as the products.