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Acid & Alkali Hazards

Acid & Alkali Hazards. D. Crowley, 2008. Acid & Alkali Hazards. To know the hazards involved when using acids and alkalis. Dangers. There are lots of acids and alkalis in the home that are relatively safe, however in the laboratory we sometimes use much more dangerous chemicals…

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Acid & Alkali Hazards

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  1. Acid & Alkali Hazards D. Crowley, 2008

  2. Acid & Alkali Hazards To know the hazards involved when using acids and alkalis

  3. Dangers • There are lots of acids and alkalis in the home that are relatively safe, however in the laboratory we sometimes use much more dangerous chemicals… • How can you tell which chemicals are safe, and which are dangerous? • Hazard symbols are used on bottles (and vehicles) that contain hazardous chemicals – they can be identified by anyone, regardless of language

  4. Dangers Toxic – can cause death is swallowed/inhaled/absorbed by skin etc… Corrosive– attacks and destroys living tissue Highly flammable– catches fire easily Irritant– will make skin red or blister Harmful– similar to toxic, but not quite as dangerous

  5. Dangers • Hazard symbols show us why the chemical is dangerous… Toxic Irritant Harmful Corrosive Highly flammable • Before we carry out any experiment, we must complete a risk assessment – we need to think about what risks there are, and what we should do if the risk occurs…

  6. Risks • Today you are going to carry out an experiment investigating household substances, identifying if it is an acid or alkali, as well as the pH of the substance (using UI) • Complete a risk assessment for the practical (consider the risks, how we can minimise them, and what to do if they occur)

  7. Risks • Sensible laboratory behaviour as always (no running) • Hair tied back • No eating, and washing hands after experiment has completed • Depending on strength of acid/alkali this could be an irritant/harmful (blistering of skin) or even corrosive (destroys skin) if there is contact • Goggles to be on at all times and hands to be washed immediately if acid/alkali touches skin • In the event of a spillage do not try to clear it up, instead inform me immediatly

  8. Experiment • Test a variety of household substances, identifying if they are an acid or alkali, and what their strength is (pH) - record your results in a table Strong acid Weak acid Neutral Weak alkali Strong alkali

  9. Acid & Alkali Examples Strong acid Weak acid Neutral Weak alkali Strong alkali Stomach acid Vinegar Skin Pure water Indigestion tablets Washing powder Oven cleaner Lemon juice Fizzy drinks Milk Blood Toothpaste

  10. Not hazardous • Why is it that lemonade is not considered hazardous, even though it contains lemon juice which has a pH of ~2? • Although lemon juice has a low pH it is not concentrated enough in lemonade to make it dangerous – although lemon juice on its own will still sting if it gets in a cut • The concentration of lemon juice in lemonade is very low (water has been added to it, which increases the overall pH closer to neutral) which is why we can drink it!

  11. Hazard Symbols

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