Sodium Bicarbonate: Uses, Grades and Safety

Sodium bicarbonate, also called sodium hydrogen carbonate, baking soda or meetha soda, is a fine white powder that is mildly alkaline. It reacts with acids to give off carbon dioxide gas, which is the fizz you see when it meets vinegar or lemon juice.

• Formula: NaHCO3
• CAS number: 144-55-8
• Molar mass: 84.01 g/mol
• Solubility: about 96 g per litre of water at 20 °C
• Heating: starts breaking down from about 50 °C, turning into sodium carbonate (washing soda), water and carbon dioxide

It is not the same as washing soda (sodium carbonate), which is much more alkaline and harsher on skin.

Azlok currently stocks two sodium bicarbonate packs.

Neither pack is labelled food grade. If you want meetha soda for cooking or baking, buy a pack labelled food grade with FSSAI details, and use it within FSSAI limits. See today's price per kg for current rates.

Cleaning and home

• Gentle scouring paste for sinks, stoves, steel utensils and tiles
• Absorbing smells in fridges, shoe racks and dustbins
• Neutralising leftover acid after oxalic acid or other acid cleaners

Lab and education

• Neutralising small acid spills on benches
• Preparing bicarbonate buffers and carbon dioxide in experiments
• The classic volcano demonstration with vinegar

Industry

• Dry powder fire extinguishers, leavening in food processing (food grade only), pH control in water and swimming pools, and some leather and textile processing

Scouring paste. Mix 3 parts sodium bicarbonate with 1 part water to a thick paste. Rub on the surface with a damp cloth or soft brush, leave for 10 to 15 minutes on burnt or greasy spots, then scrub and rinse.

Deodorising. Put 100 to 200 g in an open bowl in the fridge or a shoe rack. Replace it every month or two.

Neutralising acid. For small acid spills or after oxalic acid cleaning, sprinkle the powder or wipe with a solution of about 30 g per litre of water. Keep adding until fizzing stops, then wipe up and rinse.

Making washing soda. Spread sodium bicarbonate thinly on a tray and heat in an oven at about 200 °C for an hour, stirring once. It loses water and carbon dioxide and turns into sodium carbonate. Label the jar clearly, since washing soda is harsher.

Volcano experiment. Add 1 to 2 tablespoons to a bottle, then pour in about 100 ml vinegar with a drop of food colour.

• Sodium bicarbonate is mild, but the dust can irritate eyes and the nose. Avoid rubbing your eyes while handling it; rinse with water if any gets in.
• Wear gloves for long cleaning jobs, as the paste dries out skin.
• When reacting it with acids, use an open container. Never mix it with acid in a sealed bottle; the gas builds pressure and can burst it.
• Store in a closed, dry container. Moisture makes it cake and slowly lose strength.
• Keep lab and cleaning packs away from the kitchen and clearly labelled, so nobody uses them in food by mistake.
• Keep away from children.
• Small amounts can be dissolved in water and poured down the drain.

For lab practicals, titration work or any experiment where you need consistent results, pick the 500 g extrapure pack. For cleaning, neutralising acid after stain removal, or workshop jobs, the 1 kg general pack gives you more powder for regular use.

If cooking is your main need, wait for or choose a food grade, FSSAI-labelled product instead of either of these. Schools, labs and factories that need 25 kg or more can send a bulk inquiry.