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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: arnab321 on September 22, 2009, 04:58:47 PM

Title: Why does conc. HCl become yellow when dropped on a mosaic floor.
Post by: arnab321 on September 22, 2009, 04:58:47 PM

its only the liquid becoming temporarily yellow. does it have anything to do with release of chlorine? and how?

Title: Re: Why does conc. HCl become yellow when dropped on a mosaic floor.
Post by: Borek on September 23, 2009, 02:47:20 AM

Doubtful. Harrd to say anything not knowing anything about the floor - tiles compositin, clean/dirty, waxed or not and so on.

Title: Re: Why does conc. HCl become yellow when dropped on a mosaic floor.
Post by: renge ishyo on September 23, 2009, 06:00:51 PM

Assuming that the color has nothing to do with an actual reaction with the floor, a yellow color for HCl is common as concentrated HCl liquid itself often has a clear to light yellow color. Pour some out in a beaker and see if the yellow color is coming from the liquid itself. The yellow color in HCl is due to trace amounts of impurities such as chlorine gas, iron, or organic molecule impurities. Even if you start off with a "pure" clear HCl solution, over time it will turn more and more yellow as it is exposed to the air and as it eats into the ccontainer you are storing it in. I see this all the time as the HCl we use for the swimming pool is now quite yellow after having sat around for a while.