Topic ladders · Acids, Bases & Salts · Family table

Family table: Acids, Bases & Salts

All four rungs side by side. A younger child and an older one can do the same topic together, each at their own level.

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Step	Classes 1–3	Classes 4–7	Classes 8–10	Classes 11–12
Activity	Sour and Soapy (Early Experience)	Testing with Indicators	Neutralisation and Salt Formation	Quantitative Acid–Base Investigation
Safety	No tasting, even of food liquids: in experiments we never taste. Use only the liquids listed; never cleaners, bleach or anything from an unlabelled bottle. Keep vinegar and lemon away from eyes; if any gets in, rinse with plenty of clean water. Wash hands afterwards.	Making red cabbage indicator: chop a few cabbage leaves, cover with hot water, leave 15 minutes, and strain. You do the chopping and the hot water. Test only the liquids listed. Never test bathroom or kitchen cleaners, bleach, drain or toilet cleaner. No tasting. Keep liquids away from eyes. Turmeric stains.	–	School laboratory with a teacher; goggles on; use a pipette filler, never mouth pipetting.
What you need	Small cups of: lemon juice, vinegar, soap solution, sugar solution, water (prepared by a grown-up and labelled) No tasting: we use eyes, nose (from a distance) and fingers only	Red cabbage indicator (made by a grown-up) or turmeric paper Lemon juice, vinegar, soap solution, baking soda solution, water Small clear containers, a spoon or dropper	School laboratory only: dilute hydrochloric acid and dilute sodium hydroxide (school laboratory strength), universal indicator or phenolphthalein, dropper or burette, thermometer, evaporating dish, safety goggles	School laboratory only: standard apparatus for titration (burette, pipette, conical flask, indicator, standard solution) or a pH meter, safety goggles
Notice	Think about foods you have eaten. Which ones tasted sour? (lemon, tamarind, curd, amla) Which things at home feel slippery? (soap)	Some substances can change colour when mixed with certain liquids.	Acids and bases can cancel each other out.	The concentration of acids and bases can be determined precisely.
Guess	Which of these liquids might be sour? Which might feel slippery?	Which of your liquids will change the colour of the indicator?	What happens when an acid and a base are mixed in the right amounts?	Choose a quantitative question (concentration of acetic acid in vinegar, a pH curve, etc.).
Try	Look at each liquid. Wave the air above the cup towards your nose to smell it. Rub a drop of soap water between your fingers.	Add a few drops of each liquid to a little indicator and record the colour.	With your teacher, add the alkali to the acid a little at a time until the indicator shows neutral. Then the teacher evaporates part of the solution to obtain salt crystals.	Carry out a titration or pH investigation following proper procedures; repeat until titres agree within 0.1 cm³.
Observe	Group the liquids by how they look, smell or feel.	Group the liquids by the colour they produced.	Record temperature change, indicator colour, and appearance of the salt.	Record titres or pH data carefully and process them.
Explain	Describe the differences you noticed.	One group is acidic and another is basic. Water stays the same colour as the indicator: it is neutral.	Write a word equation (hydrochloric acid + sodium hydroxide → sodium chloride + water) and explain neutralisation.	Calculate concentrations, plot curves if relevant, and discuss accuracy.
Ask another question	Where else do we find sour or soapy things at home?	What happens to the colour if you slowly add baking soda solution to a cup of indicator with vinegar in it?	Where is neutralisation used in daily life (antacid tablets for stomach acid, lime added to acidic soil, toothpaste)?	How are acid–base titrations used in industry or environmental monitoring?

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