flinnsci.com 743
Flinn Method #3, continued
SAFETY REFERENCE CHEMICAL DISPOSAL PROCEDURES
5a
Flush the neutralized mixture down the drain with a 20-fold excess of water.
Procedure B: Potassium Metal
5b
Flush the neutralized mixture down the drain with a 20-fold excess of water.
Procedure C: Calcium and Magnesium Metal
1c
Perform this procedure in a fume hood. Wear chemical splash goggles, chemicalresistant
gloves and a lab coat or chemical-resistant apron.
1b
Perform this procedure in a fume hood. Wear chemical splash goggles, chemicalresistant
gloves and a lab coat or chemical-resistant apron.
2c
Add small increments of leftover metal (1–2 g) to 1 L of cold water (for calcium) or
dilute (1 M) hydrochloric acid (for magnesium). Stir the mixture until all the metal
has dissolved.
4c
Flush the solution down the drain with a 20-fold excess of water.
2b
Place small pieces of leftover potassium metal in a 500-mL beaker and cover with
mineral oil.
FLINN METHOD
#4a Picric Acid
Picric acid is explosive when dry. Do not touch or handle. Picric acid cannot be
disposed of by untrained personnel. You must contact a commercial waste disposal
service, the local bomb squad or fire department. Bouin’s solution contains picric
acid; treat it just as carefully as pure picric acid.
Examples
Picric acid, Bouin’s solution
Overview
Picric acid is normally sold containing 10–15% water, and in this state it is relatively
safe to handle. However, dry picric acid is very explosive. The explosion can be initiated
by friction, shock or sudden heating. Picric acid also reacts with metals to form
explosive metal picrates, which are highly sensitive to detonation. Do not attempt
to dispose of picric acid by chemical means. This procedure merely provides a
means to wet the picric acid to decrease its hazards.
Procedure
1
Wear a full face shield, chemical-resistant gloves and a lab coat or chemicalresistant
apron.
FLINN METHOD #4a continued on next page.
4a
Only after all pieces of metal are
gone, slowly add an equal volume of
water to the mixture. Neutralize with 1
M hydrochloric
acid.
No metals left
1 M
HCl
3b
Slowly add tert-butyl alcohol (at
least 21 mL per g of potassium) to the
metal at a rate to cause a reasonable
hydrogen evolution. Stir the reaction
mixture until all the pieces of metal
have dissolved.
t-Butyl Alcohol
4b
Only after all pieces of potassium
are gone, slowly add an equal volume
of water to the reaction mixture.
Neutralize with 1 M hydrochloric acid.
No metals left
1 M
HCl
3c
Using pH paper, neutralize to pH 7 with
1 M hydrochloric acid.
pH Paper
1 M
HCl
Please… Read the Narratives
Important narratives precede these specific chemical disposal methods!
Please read each narrative carefully! Do not use these procedures if you are
not comfortable with the chemistry. Do not use these procedures without
first consulting with your local government regulatory
officials. These
procedures may not be used in some jurisdictions. All procedures involve
some hazards and risks. Once again… read the narratives that precede
these specific chemical disposal methods.
/flinnsci.com
