Worksheet: Hazardous Reagents

In this worksheet, we will practice describing the correct procedures for handling hazardous reagents, including lachrymators and pyrophores.

Q1:

A reaction requires the use of 50 mL of a pyrophoric liquid. Which of the following methods for transferring the liquid would produce the greatest risk?

  • AFive transfers using a 20 mL syringe
  • BContinuous transfer via a cannula
  • CTwo transfers using a 50 mL syringe
  • DA single transfer using a 50 mL syringe
  • EA single transfer using a 100 mL syringe

Q2:

When working with a large volume of pyrophoric reagent in a laboratory, which of the following is not a necessary precaution?

  • AOther people
  • BEmergency shower
  • CFire extinguisher
  • DGlovebox
  • EFace shield

Q3:

When using a pyrophoric liquid, which of the following would not reduce the risk of the procedure?

  • AClamping the syringe when taking up the reagent
  • BUse of a cannula instead of a syringe
  • CUse of a glovebox
  • DMeasuring the reagent volume with the smallest suitable syringe
  • EOven drying glassware before contact with the reagent

Q4:

When using a pyrophoric liquid, which of the following would not reduce the risk of the procedure?

  • ADiluting the material in heptane before quenching with water
  • BUse of n-butyllithium instead of t-butyllithium
  • CAvoidance of synthetic clothing
  • DUse of pentane instead of heptane as a solvent
  • EUse of n-hexyllithium instead of n-butyllithium

Q5:

When diluting an acid, why is it best to add the concentrated acid to water, instead of adding water to the concentrated acid?

  • ADiluting in this way prevents spillage of concentrated acid.
  • BConcentrated acid may damage the container.
  • CProducing an aqueous solution with a very low pH may cause counterions to undergo reduction-oxidation reactions.
  • DIt is easier to control the release of heat and avoid boiling of the solution.
  • EThe acid may precipitate if only a small volume of water is present.

Q6:

Which of the following can react in excess with aqueous potassium cyanide to produce a solution safe for disposal as non-hazardous aqueous waste?

  • ASodium hydroxide
  • BHydrochloric acid
  • CIsopropanol
  • DSodium hypochlorite
  • EPotassium dichromate

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