Additional notes Flashcards
Water can act as both an acid and a base making it
amphoteric
If the number of hydrogen that was given was for a base what are you actually solving for
Potential of hydroxide
What is considered as weak acid
3-6
what is considered as a strong base
11-14
What is considered as a strong acid
3 below
what is considered as a weak base
8-10
Why should water be added first before acids
It will cause an explosion due to exothermic reactions
What does weight accurately mean
Using analytical balance
Is it necessary to perform titration with blank
yes
Common name of barium hydroxide
Baryte
what is carbonate error
refers to how reactive OH is to carbon atoms, which may alter the concentration of OH
Why polyolefin containers
To prevent leeching
Why are the primary standards dried
to remove impurities
sonication / water bath
the process done to prevent carbonate error
Why does some titration need residual titration
Insoluble
Sharp-end point
Slow
Volatile
Importance of filter
separates the intermediates
What temperature is Ignition conducted
700 degrees
Why should zinc oxide be ignited first
should can react with carbon dioxide to form zinc carbonate
Why is ammonium chloride added in assay of Zinc oxide
To separate undissolved components
Why should zinc oxide assay need to be gently heated
necessary to increase the rate of reaction between zinc oxide and sulfuric acid
Why should boric acid by dried and accurately weighed
To ensure that H3BO3 will be free from moisture and the exact amount of H3BO3 will be used in the assay
Why is boric acid dissolved in glycerin
boric acid is a weak acid to be titrated quantitatively in an aqueous solution with an alkali with a visual indicator, however, it can be titrated with a standard alkali in the presence of polyhydric alcohol using phenolphthalein as an indicator. Boric acid is esterified in the presence of polyhydric alcohols such as glycerol or mannitol, forming a monobasic acid that is strong enough to give a satisfactory endpoint (Glycerin makes the boric acid strong so that it may readily react with the titrant NaOH)
Why is concentration of sugar alcohol be at least 30%
to prevent complex acid
Why is glycerin used in boric acid
forms a slightly dissociated complex with the metaborate ion which prevent the reversal of the reaction
Glycerin should be neutralized with 1 N NaOH
Since it imparts acidity to the solution and thus may increase consumption of the VS
Aspirin by nature is an ester as such:
it is readily hydrolyzed when come in contact with water
What should you use to measure aspirin
weighing bottle, to reduce exposure to air
What type of titrant is the 0.5 N sodium hydroxide in Aspirin
excess titrant
What type of titrant is the 0.5 N sulfuric acid in Aspirin
Back titrant
Importance of blank titration:
for correction of data
Why should aspirin be diluted in sodium hydroxide
Since it is a weak acid
Residual titration of acidimetry
- Assay of Milk of Magnesia
- Assay of Methenamine
- Assay of Ammonium Chloride Injection
- Assay of Zinc Oxide
For nitrogen determination (in organic substances plus the
nitrogen contained in the inorganic compounds ammonia and
ammonium)
Kjeldahl Method
Residual Titration for alkalimetry
Assay of Aspirin
