BP106T Unit 2 – Acid-Base Equilibria & Volumetric Titrations

An Acid-Base Buffer is an aqueous solution consisting of a mixture of a weak acid and its conjugate base (e.g., $CH_3COOH + CH_3COONa$) or a weak base and its conjugate acid (e.g., $NH_4OH + NH_4Cl$) that possesses the property of resisting significant changes in pH upon the addition of small amounts of strong acid ($H^+$) or strong base ($OH^-$). Buffer Capacity ($\beta$, Van Slyke) is the ratio of the increment of strong acid/base added to the small resulting change in pH: $\beta = \frac{\Delta B}{\Delta \text{pH}}$. Buffer capacity is maximal when $\text{pH} = \text{pK}_a$.Buffer Solution wo solution hota hai jo thoda acid ya base milane par bhi apna pH badalne nahi deta. Henderson-Hasselbalch equation se buffer ka exact pH nikala jata hai: `pH = pKa + log([Salt] / [Acid])`. Blood ka pH 7.4 phosphate aur bicarbonate buffer se maintain rehta hai.

Antacids are alkaline pharmaceutical compounds ingested orally to neutralize hyperacidic gastric hydrochloric acid ($HCl$), raising gastric pH above 3.5 to relieve dyspepsia, heartburn, and peptic ulcer pain. Antacids do not stop gastric acid secretion; they chemically neutralize existing gastric acid. Antacids are categorized into: (1) Systemic (Absorbable) Antacids — soluble, rapidly absorbed into systemic circulation (e.g., Sodium Bicarbonate, $NaHCO_3$), which can cause systemic metabolic alkalosis and fluid retention, and (2) Non-Systemic (Non-Absorbable) Antacids — insoluble, remaining within the GI tract where their cations form insoluble basic carbonates/phosphates that are excreted in feces, posing minimal risk of systemic alkalosis (e.g., Aluminium Hydroxide Gel, Magnesium Hydroxide / Milk of Magnesia, Magnesium Trisilicate).Antacids pet ke extra hydrochloric acid (HCl) ko neutralize karte hain. Sodium bicarbonate systemic antacid hai jo khoon me ghul kar alkalosis kar sakta hai. Non-systemic me Aluminium Hydroxide lene se kabj (Constipation) hoti hai aur Magnesium Hydroxide lene se dast (Diarrhea/Laxative) lagte hain. Isliye dono ko combine karke (Digene, Gelusil) banaya jata hai taaki dono ke side effects ek dusre ko cancel kar dein.

Protectives and Adsorbents are chemically inert, insoluble, fine inorganic powders administered orally to coat inflamed intestinal mucosa, form a protective barrier against irritants, and physically adsorb bacterial enterotoxins and toxic chemicals in diarrhea (e.g., Bismuth Subcarbonate, Light Kaolin / Hydrated Aluminum Silicate). Cathartics / Purgatives are agents that accelerate intestinal evacuation of feces. Saline (Osmotic) Cathartics are poorly absorbed hypertonic inorganic salts (e.g., Magnesium Sulphate / Epsom Salt, $MgSO_4\cdot 7H_2O$; Sodium Potassium Tartrate / Rochelle Salt) that retain water within the intestinal lumen via osmotic pressure, distending the bowel and stimulating reflex peristalsis.Kaolin (mitti jaisa powder) aur Bismuth dast (diarrhea) me aanto par protective layer banate hain aur bacteria ke toxin ko sookh lete hain. Magnesium Sulphate (Epsom Salt) ek Saline Cathartic hai jo aanto me paani kheench kar pet ko 1-3 ghante me tezi se saaf karta hai.