# Chemistry, Titrations and working out how much acid is needed.

#1
Sodium hydroxide reacts with cirtric acid in a 3:1 ratio. Use this relationship to calculate the columes of citric acid in cm3 required in the following titrations for a complete neutralization.
25cm3 of 0.08 mol dm-3 Naoh and 0.025 moldm-3 citric acid.
I have managed to work out that the amount of mass required is 0.002 of the sodium hydroxide. (through the euquation used for aqueous solution (concentraction = mass/volume)). I know that this now needs to be divided by three due to the ratio above, however I am not sure if 0.0006 recurring is the correct answer. Can anyone help me find the answer with step by steps pls?
0
4 years ago
#2
(Original post by DarkIronsBarzakh)
Sodium hydroxide reacts with cirtric acid in a 3:1 ratio. Use this relationship to calculate the columes of citric acid in cm3 required in the following titrations for a complete neutralization.
25cm3 of 0.08 mol dm-3 Naoh and 0.025 moldm-3 citric acid.
I have managed to work out that the amount of mass required is 0.002 of the sodium hydroxide. (through the euquation used for aqueous solution (concentraction = mass/volume)). I know that this now needs to be divided by three due to the ratio above, however I am not sure if 0.0006 recurring is the correct answer. Can anyone help me find the answer with step by steps pls?

You are correct that the number of moles is 0.002 in NaOH (The caluclation you used i assume is (25/1000)*0.08.

Now the molar ratio between Sodium Hydroxide and the acid is 3:1. This means for every mole of citric acid, there is three moles of hydroxide. so divide 0.002 by three = 0.00067 which is the number of moles of citric acid.

Than divide 0.0067 by 0.025 (volume = moles/conc.) which equals 0.0266dm3 which than times by 1000 = 26.7cm^3.

Hope I helped!
1
4 years ago
#3
Work out how many moles of NaOH are in your solution.
This number is 3 times more than the moles of citric acid needed to react fully, from your ratio. Then u can use concentration=moles/volume
1
#4
(Original post by Audrius,C)

You are correct that the number of moles is 0.002 in NaOH (The caluclation you used i assume is (25/1000)*0.08.

Now the molar ratio between Sodium Hydroxide and the acid is 3:1. This means for every mole of citric acid, there is three moles of hydroxide. so divide 0.002 by three = 0.00067 which is the number of moles of citric acid.

Than divide 0.0067 by 0.025 (volume = moles/conc.) which equals 0.0266dm3 which than times by 1000 = 26.7cm^3.

Hope I helped!
(Original post by Audrius,C)

You are correct that the number of moles is 0.002 in NaOH (The caluclation you used i assume is (25/1000)*0.08.

Now the molar ratio between Sodium Hydroxide and the acid is 3:1. This means for every mole of citric acid, there is three moles of hydroxide. so divide 0.002 by three = 0.00067 which is the number of moles of citric acid.

Than divide 0.0067 by 0.025 (volume = moles/conc.) which equals 0.0266dm3 which than times by 1000 = 26.7cm^3.

Hope I helped!
Thanks lol, I knew there was something wrong with 0.006 as a final answer. Thank you for clarifying
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