Exploring Acid/Base Analysis Techniques

Dot-Point 5: explore acid/base analysis techniques that are applied: in industries, by Aboriginal and Torres Strait Islander Peoples, using digital probes and instruments

Acid and base analysis is a fundamental chemical process with diverse applications across industries, indigenous practices, and modern digital technology. This post delves into specific examples and explores how these techniques are applied in the wine industry, by Aboriginal and Torres Strait Islander Peoples, and with digital probes and instruments.

1. Acid/Base Analysis in the Wine Industry: Ensuring Quality Control

Case Study: Tartaric Acid Analysis

The acidity of wine significantly influences its flavour, stability, and quality. Acid/base titration is commonly used in the wine industry to determine the concentration of tartaric acid (C₄H₆O₆), a diprotic acid naturally present in grapes.

Process:
Tartaric acid is titrated with sodium hydroxide (NaOH) to measure its concentration.
Reaction:
C₄H₆O₆(aq) + 2NaOH(aq) → Na₂H₄C₄O₆(aq) + 2H₂O(l)
Significance:
Monitoring tartaric acid ensures the wine achieves a balance between acidity and sweetness, enhancing its overall quality and shelf life.

2. Pharmaceutical Industry: Determining Aspirin Purity

Case Study: Back Titration for Aspirin Analysis

Back titration is a vital technique in pharmaceutical quality control, particularly for determining the purity of aspirin (acetylsalicylic acid, ASA). Aspirin, a monoprotic weak acid, is challenging to directly titrate due to its slow dissolution in water.

Process:

Preparation: Crush an aspirin tablet and dissolve it in ethanol and excess sodium hydroxide (NaOH).
Reaction: The aspirin reacts with NaOH to ensure complete neutralization.
Excess Base Measurement: Titrate the leftover NaOH with standardized hydrochloric acid (HCl).
Blank Titration: Perform a parallel titration without aspirin to quantify the total base.
Calculation: Subtract the excess NaOH from the total base to determine the moles of ASA.

Why Back Titration?

Ensures complete reaction of ASA, overcoming solubility challenges.
Enables accurate determination of the active ingredient in aspirin tablets.

Aboriginal and Torres Strait Islander Practices: Natural Acid/Base Remedies

Indigenous Australians have demonstrated profound knowledge of natural acid/base interactions, applying them for medicinal and therapeutic purposes.

Examples:

Clay/Ochre for Stomach Acid Neutralization:
Many ochres and clays contain hydroxides (e.g., FeO(OH)·nH₂O) that neutralize stomach acid.
Reaction: OH⁻ (from ochre) + HCl (stomach acid) → H₂O + Cl⁻
This practice effectively treated acid reflux and related discomfort.
Treating Stings with Plant Alkaloids:
Indigenous plants containing basic alkaloids were used to neutralize acidic venoms from bees, ants, and marine stings. These alkaloids also provided analgesic and antiseptic benefits.
Soap Tree Leaves for Antiseptic Care:
Leaves of the soap tree, rich in saponins (acidic compounds), created antibacterial solutions when mixed with water. These solutions were used to treat cuts, rashes, and skin infections.

Digital Probes and Instruments: Modern Acid/Base Analysis

Advancements in technology have revolutionized acid/base analysis, making it faster, more accurate, and widely applicable.

Example: pH Sensors in Environmental Monitoring

Digital pH probes are used to analyse soil and water samples to monitor acidity levels in real-time. This is crucial for industries like agriculture, where soil pH impacts crop yield, and environmental science, where water quality is evaluated.