Chemistry Lecture 07 – Acids, Bases and Salts (Salts & Their Types – Part II)

Vocabulary flashcards cover definitions and key terms related to common salt, salt formation, pH nature of salts, sodium hydroxide manufacturing via the chlor-alkali process, and supporting electrochemical terminology discussed in Lecture 07.

Common salt / Table salt

Everyday edible salt that is chiefly a mixture of NaCl with small amounts of MgCl₂, CaCl₂ and KI/NaI added for iodine supplementation.

Sodium chloride (NaCl)

Chemical compound of sodium and chlorine; major constituent of common salt obtained from seawater, rock salt deposits, and inland lakes.

Iodised salt

Table salt fortified with potassium iodide (KI) or sodium iodide (NaI) to prevent iodine deficiency in humans.

Rock salt

Natural, brown solid deposits of common salt formed when prehistoric seas dried up; mined in areas like Mandi (HP) and Khewra (Pakistan).

Inland-lake salt

NaCl obtained by natural evaporation of saline inland lake waters, e.g., Sambhar Lake (India) and Great Salt Lake (USA).

Neutralisation reaction

Reaction between an acid and a base producing salt and water; one—but not the only—method of salt formation.

Neutral salt

Salt formed from a strong acid and strong base; its aqueous solution has pH ≈ 7.

Basic salt

Salt produced from a weak acid and strong base; its solution shows pH > 7 (alkaline).

Acidic salt

Salt arising from a strong acid and weak base; its solution has pH < 7 (acidic).

Brine solution

Concentrated aqueous solution of sodium chloride (NaCl) used as electrolyte in the chlor-alkali process.

Chlor-alkali process

Industrial electrolysis of aqueous NaCl that yields sodium hydroxide (main product), chlorine gas and hydrogen gas (by-products).

Sodium hydroxide (NaOH) / Caustic soda / Lye

Strong alkali manufactured mainly by the chlor-alkali process; used in soap, paper, textiles and many chemical syntheses.

Main product

The primary desired substance produced in a chemical process (e.g., NaOH in the chlor-alkali process).

By-product

Secondary substance formed alongside the main product during a chemical process (e.g., H₂ and Cl₂ from brine electrolysis).

Anode

Electrode connected to the positive terminal of a power source where oxidation (loss of electrons) occurs during electrolysis.

Cathode

Electrode connected to the negative terminal of a power source where reduction (gain of electrons) occurs during electrolysis.

Oxidation

Chemical process involving loss of electrons; occurs at the anode in electrolysis.

Reduction

Chemical process involving gain of electrons; occurs at the cathode in electrolysis.

OIL RIG mnemonic

Phrase ‘Oxidation Is Loss, Reduction Is Gain’ used to recall electron-transfer definitions of oxidation and reduction.

Effervescent antacid

Tablet containing acid (e.g., citric acid) and base (e.g., NaHCO₃) that releases CO₂ bubbles; illustrates that antacids can include an acid component.

Wasp-sting treatment

Application of a mild acid (lemon juice, vinegar) to neutralise the alkaline venom of a wasp sting.

pH of salt solution

Determined by the strengths of the parent acid and base: strong + strong ⇒ neutral; weak + strong ⇒ basic; strong + weak ⇒ acidic; weak + weak ⇒ variable.