2. Safety matters related to the use of acids and alkalis 10.7 Safety matters related to the use of acids and alkalis

3. p.50 Corrode skin, clothes, metals and marbles - Strong acids and alkalis are highly corrosive.

4. - Acids commonly used in the laboratory: Nitric acid Sulphuric acid Hydrochloric acid

5. - If acids/alkalis are splashed onto skin or eyes, it can cause serious burns. What are the treatments for these accidents? - Vapour of strong acids/alkalis may hurt the eyes and the respiratory system. How to avoid these accidents?

6. - The following household cleansers contain strong acids/alkalis: This toilet cleanser contains hydrochloric acid. These drain cleansers contain sodium hydroxide. p.50

7. Caustic ( Caustic ( 哥士的 ) oily stains. Solids of sodium hydroxide ( 哥士的 ) can be made into solution for removing oily stains. What safety precautions should we take?

8. - Commercial products containing acids or alkalis are often sold in form of concentrated solutions. What are the advantages of selling products in form of concentrated solutions? - These concentrated solutions contain low proportion of water and high proportion of acids or alkalis. => => Diluting before use

9. - For safety, we should follow proper procedures in diluting concentrated solutions. water concentrated acid/alkali p.53 Release a large amount of heat and concentrated acids/alkalis will spurt out. Should not add water to concentrated acids/alkalis

10. - Proper procedures in diluting concentrated acids/alkalis: water concentrated acid/alkali wear gloves, goggles and protective coats carry out the dilution inside a fume cupboard or ventilated area slowly add concentrated acid/alkali to a large amount of water continuously stir the solution