Quantifying Ca(OH)? Dosage for Water Neutralization: Hydrochloric Acid vs. Hydroxyacetic Acid

Water with a pH of 1 represents a highly acidic solution, and the dosage required for its neutralization with calcium hydroxide (Ca(OH)?) depends on the type of acid causing the pH value. In this discussion, we will explore the required amount of Ca(OH)? to neutralize 550 gallons of water with a pH of 1, regardless of whether it is due to hydrochloric acid (HCl) or hydroxyacetic acid (HOAc).

Understanding pH and Acidic Solutions

When dealing with water pH, the pH level of 1 indicates a strong acidic environment where the concentration of hydrogen ions, [H?], is 10 moles per liter (mol/L). Using the relationship between pH and hydrogen ion concentration, we can calculate the concentration of hydrogen ions:

pH -log[{H}] 1

H 10 mol/L

Calculation for Neutralizing Water with a pH of 1

To achieve neutralization, the moles of Ca(OH)2 required can be calculated as follows:

N 550 gal × 3.78541 L/gal × 10 mol/L 20820 mol H?

Since Ca(OH)? acts as a base, one mole of Ca(OH)2 provides two moles of OH-, which can neutralize two moles of H?. Therefore, the moles of Ca(OH)? needed are:

N 20820 mol H? / 2 10410 mol Ca(OH)?

The molar mass of Ca(OH)2 is approximately 74.02 g/mol, hence the mass of Ca(OH)2 required is:

m 10410 mol × 74.02 g/mol 77001.6 g

Converting this to kilograms, we get:

mass 77001.6 g / 1000 g/kg 7.70 kg Ca(OH)?

Impact of Different Acids on Neutralization

When the pH of 1 is caused by either hydrochloric acid (HCl) or hydroxyacetic acid (HOAc), the neutralization process might slightly differ in terms of side reactions and the efficiency of base usage.

Hydrochloric Acid (HCl): HCl is a strong acid that will fully dissociate in water. Thus, each mole of HCl will release one mole of H?. The neutralization process will be straightforward, and the dosage of Ca(OH)? will solely depend on the amount of HCl. Hydroxyacetic Acid (HOAc): HOAc is a weak acid that will partially dissociate in water, meaning only a portion of the acid molecules will release H?. The neutralization process will involve the base reacting with the available H? ions, and the dosage of Ca(OH)? will be influenced by the degree of dissociation of HOAc.

Conclusion

In conclusion, for 550 gallons of water with a pH of 1, the theoretical dosage of Ca(OH)2 required to neutralize it is 7.70 kg. While the dosage remains constant, the efficiency and side reactions during the neutralization process will differ based on whether the pH is caused by HCl or HOAc.

Understanding these nuances is crucial for effective and efficient management of water treatment and acid neutralization processes in various industries, such as manufacturing, chemical plants, and wastewater treatment facilities.