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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: portugal on May 09, 2007, 06:45:48 AM

Title: Titration calc- anaylsis of radox bath salts
Post by: portugal on May 09, 2007, 06:45:48 AM

A 25.0ml aliquot of a solution containing sodium carbonate and sodium hydrogen carbonate was titrated with 0.0800M HCl(aq). A volume of 27.50mL of 0.800M HCl(aq) was needed to reach phenolphtalein endpoint. on addition of screened methyl orange, a further 32.50mL of the acid were needed to turn this indicator to its natural colour. find the concentrations as molarities of soidu carbonate and sodium hydrogen carbonate in orginal solution??

have a go at this its getten me pscyched up coz i cant jump at it like i usually do wid first year uni chem

Title: Re: Titration calc- anaylsis of radox bath salts
Post by: Borek on May 09, 2007, 06:55:40 AM

Why do you use two different indicators?

Title: Re: Titration calc- anaylsis of radox bath salts
Post by: portugal on May 09, 2007, 11:04:09 PM

its for both endpoints as Na2CO3 is done first then NaHCO3

Title: Re: Titration calc- anaylsis of radox bath salts
Post by: Borek on May 10, 2007, 02:47:57 AM

OK

Hint: you have two unknowns and you can set up of system of equations. Of these one will be with one unknown, which makes calculations much simpler.

Title: Re: Titration calc- anaylsis of radox bath salts
Post by: portugal on May 10, 2007, 02:51:51 AM

i cant seem to get does someone want post an answer

Title: Re: Titration calc- anaylsis of radox bath salts
Post by: AWK on May 10, 2007, 04:23:35 AM

Quote from: portugal on May 09, 2007, 11:04:09 PM

its for both endpoints as Na2CO3 is done first then NaHCO3

At the first enpoint you titrate half of Na2CO3,  at the second enpoint - the rest