Hi there - I'm going to post the question as written in my book.
Three 20.0 mL samples of nitric acid are titrated with a 0.200 mol/L solution of sodium hydroxide. The results for the three trials are shown in the table below. What is the concentration of the hydrochloric acid?
Trial | 1 | 2 | 3 | average
_______________________________________
Final Burette| | | |
reading (ml) |28.20|27.90|28.00|
_______________________________________
Initial Buret|50.0 |50.0 |50.0 |
te reading(ml)
_______________________________________
Volume of
NaOH added | | | |
_______________________________________
end of question in book
my dilema:
Right off the bat I'm confused because I get a negative number for the volume added. ie. 28.20 ml - 50 ml = -21.80 ml which can't be right.
From there the rest of my answer is based on the negative number which I don't think is right. Please help me clarify how to work out the volume of the NaOH added if the final burette reading is 28.20 ml and initial burette reading is 50 ml. From there I think I can manage the rest but will probably request you verify
Thanks in advance!!!
I'm confused also. Perhaps the buret is calibrated with 50.0 at the top and zero at the bottom so you have added 50-28.2 = 21.8 mL. However I've never seen a buret calibrated that way. Furthermore, it doesn't make any sense to calibrate it in reverse. It makes more sense for those 50.0 mL initial readings to be 0.50 or 0.05 or something like that.
That's what I thought....Thank you !!!
Experiment:-determine the normaliyy and normality and strength of the given solution of sodium hydroxide provided n/10 hcl general calcutions normality and strength intial reading is 3 S.no is 0 and the final reading is 9,9.4 9.5 and volume of hcl used ?
To calculate the volume of NaOH added, you need to subtract the initial burette reading from the final burette reading. In this case, you have a final burette reading of 28.20 mL and an initial burette reading of 50.0 mL.
When subtracting these values, it's important to note that the final burette reading should be larger than the initial burette reading. If you end up with a negative number, it means that you have swapped the values.
In this case, the correct calculation would be:
Final Burette Reading - Initial Burette Reading
28.20 mL - 50.0 mL = -21.80 mL
As you correctly pointed out, this result is not physically possible and indicates an error in the values or in the way they are recorded. It seems like there might have been a mistake in the final burette reading or the initial burette reading provided in the table.
To proceed with the calculation, you would need the correct volume of NaOH added for each trial. Then, you can calculate the average volume of NaOH added by summing the volumes for the three trials and dividing by 3.
Once you have the average volume of NaOH added, you can use it to determine the concentration of the nitric acid. However, since the volume of NaOH added is not provided, it's not possible to proceed with the calculation based on the given information.
I hope this clarifies the issue and provides some guidance on how to calculate the volume of NaOH added. If you have access to the correct values or any additional information, feel free to provide it and we can continue the calculation process together.