Anachem Experiment 1 Flashcards
What are the 3 steps involved in the procedure?
- The group is precipitated with dilute HCl (hydrochloric acid) as insoluble chlorides
- Lead chloride (PbCl2) is removed from the precipitate by leaching with hot water
- Separation of AgCl from Hg2Cl2 with ammonia water
What Group I cations are included in the activity
silver, lead, and mercurous ions (absent Hg2+)
How do you test for the presence of the three ions?
Unknown sample–transfer in a test tube (+10 drops 3M HCl)–Mix then centrifugate (Speed of 2; 1 Minute)– Test for complete precipitation (+ 1 drop of 3M HCl)–Residue Wash with 10 drops of water + 1 drop of 3M HCl– stir centrifugate–white precipitate (may contain ions).
What does it mean after centrifugation the sample is still cloudy?
precipitation is not complete
After centrifugation (supernatant liquid), what will happen to the centrifugate?
The Supernatant liquid is discarded into another test tube
The Supernatant liquid is discarded into another test tube, what lab equipment is used?
Pipette/ Dropper
Unknown sample–transfer in a test tube (+10 drops 3M HCl)–Mix then centrifugate (Speed of 2; 1 Minute)– Test for complete precipitation (+ 1 drop of 3M HCl)–Residue Wash with 10 drops of water + 1 drop of 3M HCl– stir centrifugate–white precipitate. It may contain __________.
PbCl2, AgCl, Hg2Cl2
What solution is used in finding the presence of lead ions (Pb2+)?
4 drops of 1 M K2 CrO4 (Potassium Chromate)
What solution is used in separating Mercurous ions and Silver Ions?
ammonia water (NH4OH)
In testing for the presence of mercurous ions (Hg2+), what is the color of the precipitate/ residue?
black (blackens)
In testing for the presence of silver ions (Ag+), what is the color of the precipitate/ residue?
white ppt
What solution is used to check the acidity of the centrifugate
1 drop of 3M HNO3
If blue litmus paper turns to red, centrifugate is___________.
acidic
Chemical Formula of Silver ions
Ag+
Chemical Formula of lead ions
Pb^2+
