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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: damrags on November 13, 2019, 08:18:01 AM

Title: Quantifying HBr and Br
Post by: damrags on November 13, 2019, 08:18:01 AM
Dear members, I can very well use your help.

If you add Hydrogen bromide gas in water you will get hydrobromic acid. Unfortunately the same thing happens when you add bromine gas to water. Bromine also reacts with water to form hydrobromic acid.

My question is: Is there a way to quantify the hydrogen gas and bromine gas without using water? Should I change the solvent and how to quantify it?
Title: Re: Quantifying HBr and Br
Post by: AWK on November 13, 2019, 08:26:54 AM
Quote
Is there a way to quantify the hydrogen gas and bromine gas without using water?
What do you mean?
Title: Re: Quantifying HBr and Br
Post by: damrags on November 13, 2019, 08:30:45 AM
Thank you for your comment.

What I want to know is whether there is a way to distinguish hydrogen bromide and bromine. Because in water they both form hydrobromic acid. Because of this I cannot distinguish them.
Title: Re: Quantifying HBr and Br
Post by: AWK on November 13, 2019, 08:35:34 AM
Br2 + H2O = HBr + HBrO
Title: Re: Quantifying HBr and Br
Post by: chenbeier on November 13, 2019, 08:41:39 AM
Additionally bromine is brown, hydrogenbromide is colour less.
Title: Re: Quantifying HBr and Br
Post by: damrags on November 13, 2019, 08:48:39 AM
Let me explain it clearly.

I use a bed reactor for the following reaction: H2 (g) + Br2 (g) -> 2HBr (g).

The HBr gas is collected and dissolved in water making it acidic. This way I can know how much Hbr is formed.

Unfortunately an enormous amount of bromine also ends up in water and it appears that an enormous amount of Br2 in water forms hbr in water.

Thus, it is not possible to determine the actual concentration of hbr (g) because bromine itself forms hbr in water. I would like to determine the amount of Hbr gas.
Title: Re: Quantifying HBr and Br
Post by: AWK on November 13, 2019, 09:13:49 AM
You didn't invent this experiment. There is definitely instruction and recommended literature for it. There you should find answers to all doubts.
Maybe it's enough to measure the amount of hydrogen after absorbing bromine and hydrogen bromide? Bromine and hydrogen bromide can be differentiated by various chemical reactions - but this depends on the procedures possible and recommended in the laboratory instructions.
Title: Re: Quantifying HBr and Br
Post by: damrags on November 13, 2019, 10:55:23 AM
I was thinking of using a different solvent instead of water. Does anyone have suggestions?