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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: victor on November 28, 2005, 08:15:31 AM

Title: pH exceeding the limit
Post by: victor on November 28, 2005, 08:15:31 AM
I oftenly argue with some of the chemistry people (because I'm a biology people) that is there any pH that minus??
My lecturer said that the limitation of pH must be between 0 - 14. But, how about high concentrated acids?? if we calculate it, we'll get a minus in pH right??
Now, how about calculating high concentrated bases?? could we get pH>14 (e.g. 16 or 17)??
Title: Re:pH exceeding the limit
Post by: AWK on November 28, 2005, 08:21:46 AM
pH of water solutions can be slightly less than 0 or slightly greater than 14
Title: Re:pH exceeding the limit
Post by: Borek on November 28, 2005, 08:30:35 AM
pH scale (http://www.chembuddy.com/?left=pH-calculation&right=pH-scale)
Title: Re:pH exceeding the limit
Post by: Bakegaku on November 29, 2005, 03:25:44 PM
I think I remember reading in Guiness World Records, for most acidic water, they found some water in a mine with a pH of about -3.5.

Considering that's supposedly the most acidic I guess there's not too much you can do to make it go lower... ::)
Title: Re:pH exceeding the limit
Post by: Borek on November 29, 2005, 03:29:23 PM
they found some water in a mine with a pH of about -3.5

Just remember we are talking about activity scale, not concentration scale!
Title: Re:pH exceeding the limit
Post by: lemonoman on November 30, 2005, 02:18:37 AM
Just remember we are talking about activity scale, not concentration scale!

Oh yeeeeeaaaaahhhhh...so Ionic strength, etc. will play a role!
Title: Re:pH exceeding the limit
Post by: constant thinker on December 01, 2005, 09:03:04 PM
Also faulty/not calibrated equipment.

I got a pH reading from an uncalibrated sensor of -10.3 in a solution that should've only been 2.
Title: Re:pH exceeding the limit
Post by: mike on December 01, 2005, 09:05:02 PM
Quote
Also faulty/not calibrated equipment.

I got a pH reading from an uncalibrated sensor of -10.3 in a solution that should've only been 2.

is this a random or systematic error?
Title: Re:pH exceeding the limit
Post by: constant thinker on December 01, 2005, 09:08:53 PM
Just a random error I guess. I was astounded to see -10 at first. Then after calibration it went to normal.
Title: Re:pH exceeding the limit
Post by: mike on December 01, 2005, 09:33:58 PM
In fact this would be a systematic error.

You could still take precise measurments with the pH metre they would not be accurate though. :)
Title: Re:pH exceeding the limit
Post by: victor on December 02, 2005, 06:20:54 AM
Oh yeeeeeaaaaahhhhh...so Ionic strength, etc. will play a role!

do not think that all ionic acids would give the highest acid level....the newly invented acid molecule named carborant acid have the acid level exceeding hundreds times greater compared to high concentrated sulphate acid...and carborant acid have the molecular name for CHB11Cl11...bonded covalently... ;D