Class X Science – Acids, Bases & Salts

Vocabulary flashcards covering definitions, properties, examples, uses, naturally occurring acids, and types of indicators discussed in the Class X Science lecture on Acids, Bases, and Salts.

Acid (chemical definition)

A substance that donates protons (H⁺ ions) during a chemical reaction.

Base (chemical definition)

A substance that accepts protons or donates hydroxide ions (OH⁻) in a chemical reaction.

Taste of acids

Sour

Taste of bases

Bitter

Touch of bases

Slippery or soapy feel

Litmus test for acids

Turn blue litmus paper red.

Litmus test for bases

Turn red litmus paper blue.

Carbonic acid – main use

Added to aerated (carbonated) drinks.

Sulphuric acid – industrial use

Used in car batteries and paints.

Tartaric acid – industry

Employed in wine manufacturing and some aspirins.

Nitric acid – agricultural use

Key ingredient in fertilizer production.

Acetic acid

The acid in vinegar (CH₃COOH).

Hydrochloric acid (biological use)

Present in gastric juice, aids digestion.

Salicylic acid

Raw material for making aspirin tablets.

Sodium hydroxide (NaOH)

Strong base used in soap production.

Calcium hydroxide

Base used in cement and white-washing.

Sodium carbonate (Na₂CO₃)

Base used in many detergents.

Sodium fluoride

Added to toothpaste to prevent cavities.

Ammonia (NH₃)

Base commonly used in fertilizers.

Acetic acid – natural source

Found in vinegar from fermented food.

Lactic acid – natural source

Present in sour milk (curd).

Citric acid – natural sources

Occurs in oranges and lemons.

Tartaric acid – natural source

Found in tamarind.

Oxalic acid – natural source

Present in tomatoes.

Methanoic (formic) acid – natural source

Found in ant and nettle stings.

Indicator (general definition)

A substance that changes color or smell to show whether a sample is acidic, basic, or neutral.

Litmus

Natural indicator (pale purple) that turns red in acid and blue in base.

Turmeric as indicator

Natural indicator; yellow remains yellow in acid but turns red in base.

Hydrangea flower pigment

Natural indicator; flowers are blue in acid soils and pink in basic soils.

Phenolphthalein

Synthetic indicator; colorless in acids, pink in bases.

Methyl orange

Synthetic indicator; red in acids, yellow in bases.

Olfactory indicator

Substance whose odor changes in acidic or basic solutions.

Onion extract as olfactory indicator

Smell is retained in acid but diminishes in base.

Vanilla extract (indicator)

Smell is retained in acid and vanishes in base.

Clove oil (indicator)

Smell is retained in acid and changes/diminishes in base.