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Chemistry mole calculation problem (help me)
xim7007:
50 cm3 of a solution of citric acid, Mr = 192, containing 19.2 g dm–3 reacted with 50 cm3 of a
solution of sodium hydroxide containing 12 g dm–3. Citric acid can be represented by the
formula HxA, where x represents the number of hydrogen atoms in the molecule. Use the
data above to calculate the number of moles of sodium hydroxide that react with one mole
of citric acid and hence find the value of x. Can anyone ans this question explaining how to find the value of X? :)
Saladin:
--- Quote from: xim7007 on August 20, 2010, 06:47:20 pm ---50 cm3 of a solution of citric acid, Mr = 192, containing 19.2 g dm–3 reacted with 50 cm3 of a
solution of sodium hydroxide containing 12 g dm–3. Citric acid can be represented by the
formula HxA, where x represents the number of hydrogen atoms in the molecule. Use the
data above to calculate the number of moles of sodium hydroxide that react with one mole
of citric acid and hence find the value of x. Can anyone ans this question explaining how to find the value of X? :)
--- End quote ---
On it now, will post as soon as possible! :D
Saladin:
First, you need to calculate the number of moles of Citric acid present.
Therefore one mole of Citric Acid reacts with one mole of NaOH. Now, you can see that the NaOH particle can make two ions, Na+ and OH-.
So, therefore as there is a one to one ratio and NaOH can only produce one mole of hydroxide ions per mole of compound, this is an acid with a single Hydrogen atom in each molecule, as an acid and a base will make water.
H++OH-=H2O
xim7007:
I still don't understand.. what would be the value of X?... Concentrations are given in g/dm3
Saladin:
--- Quote from: xim7007 on August 20, 2010, 07:07:32 pm ---I still don't understand.. what would be the value of X?... Concentrations are given in g/dm3
--- End quote ---
The value for X is 1, because there is 1 hydrogen in each molecule of Citric Acid.
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