Acids, Bases and Salts Lecture Notes

Comprehensive vocabulary flashcards covering the definitions, chemical properties, indicators, pH scale, and important salts from the Acids, Bases, and Salts lecture.

Acids

Substances that donate protons ($H^+$ ions) during a chemical reaction, typically featuring a sour taste and the ability to turn blue litmus paper red.

Bases

Substances that either accept protons ($H^+$ ions) or donate hydroxide ions ($OH^-$) in a chemical reaction; they typically have a bitter taste and feel slippery or soapy.

Indicators

Substances that change their color or smell in the presence of an acid or a base to help identify the nature of a given substance.

Litmus

A natural indicator that is pale purple (mauve) in neutral solution, turning red in acidic solutions and blue in basic solutions.

Phenolphthalein

A synthetic indicator that is colorless in acidic solutions and turns pink in basic solutions.

Methyl Orange

A synthetic indicator that turns red in acidic solutions and yellow in basic solutions.

Olfactory Indicators

Substances whose smell changes depending on whether they are in acidic or basic solutions, such as onion extract, vanilla extract, and clove oil.

Neutralization Reaction

A chemical reaction where an acid and a base react to form salt and water, involving the combination of $H^+$ and $OH^-$ ions.

Metallic Oxides

Compounds that react with acids to produce salt and water; they are considered basic oxides.

Non-Metallic Oxides

Compounds that react with bases to produce salt and water, indicating that they are acidic in nature.

Electrolytes

Substances that conduct electricity because they produce ions in water; both acids and bases act as electrolytes.

Hydronium Ion

The ion represented as $H_3O^+$, formed when a hydrogen ion ($H^+$) combines with a water molecule in an aqueous solution.

Alkalis

Bases that are soluble in water, such as Sodium Hydroxide ($NaOH$).

Strong Acid

An acid that completely ionizes in aqueous solution to release a high concentration of $H^+$ ions, such as Hydrochloric acid ($HCl$).

Weak Acid

An acid that only partially ionizes in water, resulting in a lower concentration of $H^+$ ions, such as Acetic acid ($CH_3COOH$).

pH Scale

A scale ranging from $0$ to $14$ used to measure the strength of acids (pH < 7) and bases (pH > 7) based on hydrogen ion concentration.

Universal Indicator

A mixture of several indicators that shows different colors at different pH values across the entire pH scale from $0$ to $14$.

Antacids

Mild bases, such as magnesium hydroxide ($Mg(OH)_2$) or Milk of Magnesia, used to neutralize excess stomach acid during digestion.

Acid Rain

Rainwater with a pH below $5.6$ resulting from $SO_2$ and $NO_2$ reacting with water to form sulphuric and nitric acids.

Salts

Ionic compounds composed of positively charged cations and negatively charged anions held together by ionic bonds.

Chlor-alkali Process

The industrial electrolysis of aqueous sodium chloride (brine) which produces sodium hydroxide ($NaOH$), chlorine gas ($Cl_2$), and hydrogen gas ($H_2$).

Bleaching Powder

Calcium oxychloride ($CaOCl_2$), produced by the reaction of chlorine gas with dry slaked lime ($Ca(OH)_2$).

Baking Soda

Sodium hydrogen carbonate ($NaHCO_3$), produced using sodium chloride, water, carbon dioxide, and ammonia.

Washing Soda

Sodium carbonate decahydrate ($Na_2CO_3 \times 10H_2O$), obtained by the recrystallization of sodium carbonate.

Water of Crystallization

A fixed number of water molecules present in the crystal structure of certain salts, such as the five molecules in Copper Sulphate ($CuSO_4 \times 5H_2O$).

Plaster of Paris (POP)

Calcium sulfate hemihydrate ($CaSO_4 \times \frac{1}{2}H_2O$), produced by heating gypsum ($CaSO_4 \times 2H_2O$) to $373\,K$ ($100^{\circ}C$).

Dead Burnt Plaster

Anhydrous calcium sulfate formed when Plaster of Paris is heated above $200^{\circ}C$, causing the loss of all water of crystallization.