Applications & Explore Online ലായനികൾ

Solutions, suspensions and colloids are part of every Kerala day: turpentine for the painter's brushes, chlorine in our drinking water, kalkandam in the temple prasadam, fizz in a soda bottle, mist on the Munnar road, milk and butter in the kitchen and 916 gold in the jewellery shop. Every section below has a small animation, the idea at work, and a sample exam question. The page ends with a hub of links to explore online.

1. Cleaning paint brushes: turpentine, not water

like dissolves like At the science fair the enamel paint on Rahul's hands would not wash off with water, but a little turpentine took it off at once. Enamel paint, grease and tar are non-polar നോൺപോളാർ; water is polar പോളാർ. Turpentine, kerosene and petrol are non-polar organic solvents ഓർഗാനിക് ലായകങ്ങൾ, so they dissolve paint and grease. That is why painters clean brushes in turpentine and mechanics wipe grease with kerosene, and why salt and sugar, which are polar, dissolve in water but not in kerosene.

2. Saline drips and ORS: mass percentage in hospitals go further

mass percentage The “drip” given in hospitals is often normal saline: a solution of common salt in very pure water, about 0.9 % salt. ORS (oral rehydration solution), given when a person loses water and salts through diarrhoea, is a solution of salts and glucose made in exactly the amount of clean water printed on the packet. In both, the amount of solute in a definite amount of solution, the concentration ലായനിയുടെ ഗാഢത, must be correct: too dilute or too concentrated would not help the body. These are medicines: they are prepared and given as a doctor or health worker advises.

3. Bleaching solution and chlorine in drinking water: % and ppm

mass % · ppm The bleaching solution sold for cleaning contains 3.62 % sodium hypochlorite (NaOCl): 3.62 g in every 100 g of solution. When the amount of solute is extremely small, percentage gives awkward numbers, so we use parts per million (ppm) പാർട്സ് പെർ മില്ല്യൺ (ppm): parts of solute in 10⁶ (one million) parts of solution. Water authorities add a tiny amount of chlorine to drinking water to kill germs; the textbook gives about 4 ppm. One litre of water has a mass of about 1 kg = 1 000 000 mg, so 4 ppm means about 4 mg of chlorine in 1 L.

4. Kalkandam: sugar crystals from a supersaturated syrup

supersaturation · crystallization Kalkandam (sugar candy), given as prasadam in temples, is made from a supersaturated അതിപൂരിത ലായനി sugar syrup. A lot of sugar is dissolved in hot water, the syrup is cleaned and then left to cool slowly and undisturbed with threads hanging in it. As it cools, the syrup holds more sugar than it can at that temperature; the extra sugar comes out as big, clear crystals on the threads over several days. This is crystallization പരലീകരണം, just like the growing copper sulphate crystal on page 5. go further About 200 g of sugar saturates 100 g of water at 20 °C, but nearly 490 g near 100 °C.

5. Fish gasping on a hot afternoon: oxygen in warm water

gas solubility · temperature Fish breathe the oxygen dissolved in water. The solubility of a gas decreases as the temperature rises: from the textbook graph (Let us assess, Q9) oxygen falls from about 0.0068 g to 0.004 g per 100 g of water between 0 °C and 20 °C, and to about 0.003 g at 40 °C. On a hot summer afternoon, in a shallow pond or a fish tank in the sun, the water holds less oxygen, so fish come up to the surface and gasp. Hot water released from factories, and rotting waste that uses up oxygen, make it worse. go further The graph values are for water in contact with pure oxygen; water in contact with air holds less, but it follows the same trend.

6. Soda: carbon dioxide under pressure

gas solubility · pressure In a soda factory, carbon dioxide is dissolved in water at high pressure and the bottle is sealed. In the closed bottle there are no bubbles. When the cap is opened the pressure falls to the air pressure; the water can no longer hold so much gas, and CO₂ escapes as bubbles. A warm soda fizzes over and goes flat quickly, because a gas is less soluble at a higher temperature; that is why the juice shop keeps soda bottles in the fridge. The factor that keeps the gas in the soda is pressure.

7. “Shake well before use”: syrup or suspension?

suspension A clear cough syrup is a true solution യഥാർഥ ലായനി: its particles are tiny and never settle, so it needs no shaking. Ayurvedic kashayam, some antacids and calamine lotion are suspensions സസ്പെൻഷൻ: their particles are larger than 1000 nm, so they slowly settle to the bottom. The label “shake well before use” makes sure every dose has the same amount of medicine.

8. Mist on the Munnar road: the Tyndall effect

colloid · Tyndall effect Drive up to Munnar or Wayanad on a winter night and the headlight beams look like solid white cones in the mist (മൂടൽമഞ്ഞ്). Mist and clouds are colloids: tiny water droplets (liquid) spread in air (gas), a liquid aerosol. The droplets are the right size (1–1000 nm and a little larger) to scatter light, so the path of the beam becomes visible. This is the Tyndall effect ടിൻഡൽ പ്രഭാവം. On a clear night the beam itself is invisible: we see only the lit road. The same effect shows sunbeams through the trees of a misty forest, the beam of a cinema projector in a dusty hall and light in smoke.

9. Milk, curd, butter and ghee: colloids in the kitchen

types of colloids Milk is a colloid: tiny drops of fat (liquid) spread through water (liquid), an emulsion. Churning curd or cream makes the fat drops join into butter, in which tiny drops of water are held in solid fat; the textbook lists butter, jam and cheese as gels (liquid dispersed in a solid). When butter is heated to make ghee, the water boils off and the milk solids are removed, so ghee is almost pure butterfat and no longer a colloid. go further Curd is also a gel: the milk proteins form a soft network that traps the water.

10. Reading the label on a bottled drink

additives · stabilisers · preservatives Every packed food in India must carry a label with the ingredients, the date of manufacture and “best before”, a veg/non-veg mark and the FSSAI licence number (the Food Safety and Standards Authority of India). Additives are often written with their INS code numbers. Using Table 6.5 of the textbook you can recognise the colours (tartrazine – yellow, erythrosine – red, indigo carmine – blue), the preservatives പ്രിസർവേറ്റീവുകൾ (sodium benzoate, sorbic acid) and the stabilisers സ്റ്റെബിലൈസറുകൾ (such as glyceryl ester of rosin) that keep the particles of an artificial drink കൃത്രിമ പാനീയങ്ങൾ from settling.

11. 916 gold in Thrissur's jewellery shops: a solid solution

solid solution · mass percentage Pure gold is too soft for ornaments, so jewellers mix it with a little silver and copper. A 916 hallmark means 916 g of pure gold in 1000 g of the ornament (91.6 %); the rest is silver and copper. The metals are melted together and mixed evenly, so the ornament is a solid solution ഖരലായനി, an alloy ലോഹസങ്കരം, with gold as the solvent. go further Purity is also given in carats out of 24: 916 gold is 22 carat (22 ÷ 24 ≈ 0.917); 750 gold is 18 carat.

🌐 Explore online – resources hub

Everything in this guide works offline. The links below are extras: articles and simulations from trusted sources, grouped by topic. They need internet and open in a new tab, so you will not lose your place here. Ask a parent or teacher before you go online.

Solutions, solutes and solvents

Concentration and mass percentage

Saturation, crystals and solubility

Suspensions, colloids and the Tyndall effect

Drinks, additives and food safety