Exploring Substances: Acidic, Basic and Neutral

These vocabulary flashcards cover the key concepts of Chapter 2: Exploring Substances, including types of substances, various indicators, organic acids, and neutralization reactions.

Indicator

A special substance that indicates whether a solution is acidic, basic, or neutral.

Litmus

A natural indicator obtained from lichens used to identify acidic and basic substances, available as blue and red paper strips or solution.

Acid-base indicators

Substances that give different colours in acid and base, such as litmus, red rose extract, and beetroot extract.

Acidic substances

Substances that have a sour taste and turn blue litmus red, such as lemon juice and vinegar.

Basic substances

Substances that have a bitter taste, are soapy to touch, and turn red litmus blue, such as soap solution and baking soda solution.

Neutral substances

Substances that are tasteless, sweet, or salty and show no colour changes with litmus, such as salt solution and sugar solution.

Citric acid

The acid found in lemons.

Lactic acid

The acid found in curd.

Tartaric acid

The acid found in tamarind, unripe mango, and grapes.

Acetic acid

The acid found in vinegar.

Oxalic acid

The acid found in tomatoes.

Ascorbic acid (vitamin C)

The acid found in amla.

Malic acid

The acid found in apples.

Red rose extract

An acid-base indicator that gives a red colour in acidic solutions and a green colour in basic solutions.

Olfactory indicators

Substances that change their odor in an acidic or basic solution, such as onion extract and vanilla essence.

Onion Extract

An olfactory indicator that retains its pungent smell in acidic solutions but becomes odorless in basic solutions.

Vanilla Essence

An olfactory indicator that retains its sweet smell in acidic solutions but loses it in basic solutions.

Turmeric paper

A natural indicator that remains yellow (no change) in acidic solutions and turns reddish brown in basic solutions.

Red hibiscus

A natural indicator that turns dark pink in acidic solutions and green in basic solutions.

Neutralization reaction

A chemical reaction where an acid and a base react to form salt, water, and heat: $Acid + Base \rightarrow Salt + Water + Heat$

Formic acid

The acid injected by an ant during a bite, causing pain, swelling, and irritation.

Baking soda solution

A mild base used to neutralize formic acid from an ant bite to provide relief.

Soil Acidity Treatment

The process of adding limewater (calcium hydroxide solution) or powdered lime (calcium oxide) to neutralize soil that is too acidic from chemical fertilizers.

Soil Basicity Treatment

The process of adding organic matter such as compost or manure, which releases acids during decomposition to neutralize excess base in the soil.

Industrial Waste Treatment

The process of treating acidic factory waste with basic substances before releasing it into water bodies to prevent harm to aquatic life.