To determine the enthalpy of neutralization of a strong acid (HCl) with a strong base (NaOH).
Thermodynamics and Enthalpy change
Neutralization Enthalpy of strong Base and strong Acid
The neutralization process of enthalpy changes is constant for strong acid (HCl) and base (NaOH). This is due to the ions being completely dissolved in acid and base. When a strong acid, such as hydrochloric acid (HCl), reacts with a strong base, such as sodium hydroxide (NaOH), a neutralization reaction occurs. The general equation for this reaction is:
Neutralization is involved between the H+ and OH- ions. The H+ ions and the OH- ions are combined, yielding the result of H2O (l) (water molecule). The neutralization reaction gives out the combination of one equivalent of hydrogen ions with one equivalent of hydroxyl ions.
Consider this,
This can be written as (Chemical balancing demonstrated by cancelling accordingly)
The overall reaction after the chemical balancing
The neutralization reaction of strong acid and base results in the formation of water by combining H+ and OH− ions.
The calorimeter and the enthalpy change
The enthalpy changes for this experiment can be performed by using the calorimeter. In this setup, the known quantities of the acid and base are mixed, and the temperature change in the solution is to be measured. The heat evolved in the neutralization process of acid with a base. The heat is either absorbed or released at a constant temperature. Since the reaction process is exothermic, the results are always negative.
Fig.1 Setup of the Calorimeter
The obtained temperature change, the known heating capacity of the calorimeter, and the heat released or absorbed by the reaction can be determined by the equation:
Where:
∆q is the heat released or absorbed by the reaction.
m is the mass of the solution.
c is the specific heat capacity of the solution.
ΔT is the change in temperature of the solution.
The enthalpy change (ΔH) of the reaction is calculated by using the equation of
Where n is the number of moles of the limiting constant.
Calculation of the neutralization of enthalpy change
The enthalpy changes during the neutralization of 1.0M HCl = (200 x W) x (t1 – t2) x 4.18
The enthalpy changes during the neutralization =
Applications of the neutralization of Strong acid and Base
Industry | Neutralization | Examples |
Food and beverage | Adjust and neutralize the pH of food products. | The conversion processing of curding milk to form curds in cheese production. |
Water Treatment | Adjust the pH of acidic and basic water during the process of water conversion. | Treating acidic industrial wastewater with base sodium hydroxide to avoid water pollution in the environment. |
Pharmaceuticals and Medicine | The neutralization reactions were applied to produce salts from drugs. Neutralizing the acidic or basic nature improves stability, solubility, and bioavailability and makes them for medicinal use. | Production of aspirin In this, the purest form of aspirin is neutralized with the base (NaOH) to avoid stomach irritation. |
Students will learn and understand: