Conisder the following and briefly explain what would be the effect on the calcu
ID: 1061666 • Letter: C
Question
Conisder the following and briefly explain what would be the effect on the calculated analyte concentration; i.e. why would the calculated analyte concentration be higher, lower, or unchanged than the actual value if: the last drop of base was not rinsed from the buret into the reaction flask? the reaction flask contained traces of water in it before the acid was added with the volumetric pipet? the volumetric pipet used to transfer the acid solution contained traces of water? Commerical lye is an alkaline mixture that contains mainly sodium hydroxide, but major impurities include sodium chloride, sodium carbonate, sodium chlorate, sodium sulfate, potassium and heavy metals such as iron and nickel.A 0.8500 g sample of commerical lye is dissolved in water and titrated with 35.00 mL of 0.5377 M HCl. Write the balanced equation. What is the percent purity of the lye sample?(i.e., what is the mass percent of NaOH in the lye?Explanation / Answer
3a. If the last drop of base is not rinsed from the buret to reaction flask containing acid, then it does not indicate the end point correctly and require more base to get the end point. (end point is detected by color change where all the acid get neutralized with base). So, the calculated analyte concentration will be higher than actual value
3b. If the reaction flask contain traces of water before acid was added with pipet, the concentration of the acid decreases because of dilution of acid with traces of water. Then calculated analyte concentration will be lower than actual value.
3c. If the volumetric pipet contain traces of water that is used to transfer the acid then the concentration of the acid decreases as the dilution of acid with traces of water. Then calculated analyte concentration will be lower than actual value.
The above answers 3b and 3c can be understood by relation
V1M1=V2M2
where V1 and V2 initial and final volumes
and M1 and M2 are initial and final concentrations of acid
as the volume increases the concentration decreases.