Chemicals Used in Daily Life: Food Preservatives, Cleaning Chemicals, Safety Precautions & Industrial Chemical Pollution – Class 10 Science Notes

1. Introduction to Food Preservatives and Their Proper Uses

What Are Food Preservatives?

Food preservatives are chemical substances added to food to prevent the growth of microorganisms, delay spoilage, and extend shelf life.

They help maintain food quality, taste, and safety during storage and transportation.

Common Food Preservatives and Their Uses

PreservativeChemical Name / CodeUses
SaltSodium chloride (NaCl)Preserving meat, fish, and pickles
SugarSucroseJams, jellies, juices
VinegarAcetic acid (CH₃COOH)Pickles, sauces
Sodium benzoateC₆H₅COONaSoft drinks, fruit juices
Sodium metabisulphiteNa₂S₂O₅Juices, dried fruits
Citric acidC₆H₈O₇Soft drinks, fruit-based items
Nitrates & nitritesNaNO₃, NaNO₂Processed meat & sausages

Proper Uses

  • Use preservatives in limited quantities as recommended.

  • Avoid excessive use to prevent health risks.

  • Check the manufacturing date and expiry date on packaged food.

2. Chemicals Used for Cleanliness and Their Proper Uses

Chemicals used for cleanliness are essential to maintain hygiene, kill germs, and prevent diseases. These include antiseptics, disinfectants, soaps, and detergents.

2.1 Types of Cleaning Chemicals

A. Soaps

  • Made from fatty acids and sodium/potassium hydroxide (saponification).

  • Used for bathing and washing clothes.

B. Detergents

  • Manufactured from sulphuric acid derivatives.

  • Effective in hard water for cleaning clothes and utensils.

C. Disinfectants

  • Kill or inhibit harmful microbes on non-living surfaces.

  • Examples: Phenol, bleaching powder (CaOCl₂), Lysol.

D. Antiseptics

  • Applied to living tissues like skin cuts and wounds.

  • Examples: Dettol (chloroxylenol), tincture iodine, boric acid.

E. Bleaching Agents

  • Bleaching powder, hydrogen peroxide.

  • Used for stain removal, water purification, and disinfection.

Proper Uses

  • Use disinfectants for surfaces like floors and toilets.

  • Use antiseptics only on skin; never drink or inhale.

  • Dilute strong chemicals before use.

  • Avoid mixing different cleaning chemicals.

3. Precautions While Storing and Using Poisonous Chemicals

Poisonous chemicals include acids, ammonia, insecticides, pesticides, herbicides, etc. Improper handling can cause poisoning, burns, or pollution.

Precautions

A. Storage Precautions

  • Store chemicals in original containers with proper labels.

  • Keep away from children and pets.

  • Store in cool, dry, and ventilated places.

  • Keep flammable chemicals away from fire.

B. Usage Precautions

  • Wear gloves, masks, and eye protection while handling chemicals.

  • Do not inhale fumes or let chemicals contact skin.

  • Avoid eating or drinking near chemical storage.

  • Always follow the instructions on labels.

  • Wash your hands thoroughly after use.

C. Disposal Precautions

  • Dispose of expired or unused chemicals safely.

  • Do not pour toxic chemicals into drains or rivers.

  • Use proper waste collection systems.

4. Industrial Chemicals Causing Chemical Pollution & Their Control Measures

Industries release many toxic chemicals that cause land, air, and water pollution.

4.1 Common Industrial Pollutants

Chemical PollutantSource IndustriesHarmful Effects
Sulphur dioxide (SO₂)Power plants, factoriesAcid rain, respiratory diseases
Nitrogen oxides (NOₓ)Vehicles, chemical industriesSmog, acid rain
Heavy metals (Hg, Pb, Cd)Batteries, paint, miningWater pollution, poisoning
Chlorine compoundsPlastics, bleaching industriesWater contamination
Dyes & toxic effluentsTextile factoriesWater pollution
Petroleum hydrocarbonsOil refineriesMarine pollution
Pesticides & fertilizersAgriculture runoffSoil infertility, health hazards

4.2 Control Measures for Chemical Pollution

A. Industrial-Level Measures

  • Install wastewater treatment plants (WWTPs).

  • Use filters and scrubbers to reduce gaseous emissions.

  • Follow proper chemical storage and disposal guidelines.

  • Shift to eco-friendly chemicals wherever possible.

B. Government-Level Measures

  • Enforce environmental laws and pollution control standards.

  • Regular monitoring of industries.

  • Promote green technologies.

C. Community-Level Measures

  • Awareness about harmful chemicals.

  • Reduce use of plastic and chemical-heavy products.

  • Encourage recycling and waste segregation.

Conclusion (SEO-Friendly)

Chemicals play a vital role in our daily life—from preserving food to maintaining cleanliness. However, improper use and handling of chemicals can lead to health hazards and pollution. Understanding preservatives, cleaning chemicals, storage precautions, and industrial pollutants helps Class 10/SEE/NEB students make informed, safe, and environmentally responsible decisions.

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