SAFE WORK PROCEDURE
LOCATION
VMC
WRITTEN BY: APPROVED BY:
Science Team
Acid-Base Indicators and pH
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DATE CREATED
WS&H
LAST REVISION
June 27, 2014
New
PERSONAL PROTECTION EQUIPMENT (PPE)
Safety glasses or face shield must be worn at all
times in work areas.
Long and loose hair must be tied back
Appropriate footwear must be worn. Shoe must
be fully enclosed. No open toed shoes.
Close fitting/protective clothing must be worn.
Remove strings hanging from pullovers/sweaters.
Rings and jewelry (long necklaces / bracelets,
etc.) must not be worn.
HAZARDS PRESENT
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Chemical burns
Absorption of Chemicals.
Inhalation of Chemicals.
Ingestion of Chemicals.
Slips / trips & falls
Chemical hazards
ADDITIONAL
REQUIREMENTS
APPARATUS / MATERIALS
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Well plate
White paper
Eyedroppers
Distilled water
0.1M HCl
0.1M NaOH
Universal indicator
Methyl orange indicator
Phenolphthalein indicator
Bromothymol blue indicator
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Equipment orientation
WHMIS training
SAFE WORK PROCEDURE
1. Don all personal protective equipment including: safety glasses, & protective nitrile gloves
(where required). Ensure all loose clothing is either removed or tied back. Remove any jewelry
and tie back long hair.
2. Place the well plate on white paper with the lettered columns on the left. Place 9 drops of
distilled water into wells 2 through 11 of rows A, B, C, and D.
3. Add 10 drops of 0.1M HCl to wells A1, B1, C1, and D1. Be careful when handling HCl.
4. Add 10 drops of 0.1M NaOH to wells A12, B12, C12, and D12. Be careful when handling
NaOH.
5. Transfer 1 drop of HCl from well A1 to well A2. Mix by drawing the contents of well A2 into the
eyedropper and then returning the liquid to well A2.
6. Transfer 1 drop fro well A2 to well A3, again mixing by drawing the contents of well A3 into an
eyedropper and returning the contents to well A3. Continue the serial dilution in this manner
through to and including well 6.
SAFE WORK PROCEDURE
Acid-Base Indicators and pH
Page 2 of 2
7. Repeat steps 4 and 5 for rows B, C, and D.
8. Transfer 1 drop of NaOH solution from well A12 to well A11. Mix the drawing up the contents of
well A11 into an eyedropper and then returning the liquid to well A11.
9. Now transfer 1 drop from well A11 to well A10, again mixing by drawing the contents of well
A10 into an eyedropper and returning the contents to well A10. Continue the serial dilution in
this manner backwards through to and including well 8.
10. Repeat steps 8 and 9 or rows B, C, and D.
11. You now have 4 rows of diluted solutions containing varying amounts of acid and base, each
1/10th of the acid of the well to its left and 1/10th of the base of the well to its right. Well numbers
indicate the approximate pH of the solutions in each well (e.g., well 4 has a pH of 4 and well 9
has a pH of 9).
12. Add 1 drop of universal indicator to each well in row A.
13. Add 1 drop of methyl orange to each well in row B.
14. Add 1 drop of phenolphthalein to each well in row C.
15. Add 1 drop of bromothymol blue to each well in row D.
16. Clean up your workstation and wash your hands thoroughly.
REGULATORY REQUIREMENTS
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WS&H Act W210, Section 4, 5
Mb. Regulations 217/2006,
Part 16, (Machines / Tools & Robots) Sections 16.1-16.18)
Part 35, (WHMIS Application)
Part 36, (Chemical & Biological Substances Application)