Need help with some results of ph and ionic substances

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Ssanchez11
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Need help with some results of ph and ionic substances

Post by Ssanchez11 »

Well, i have the following problem, i recorded in an experiment the pH of a solution of h2o plus nacl, exactly with 16 mg of nacl in 50ml of h20, 50 mg and 138 mg in 50 ml of h2o. The proboem is that my hypothesis was that the ph wouldnt show much change, but it actually changed from 6.91 to 6.55 to 6.23 respectivily. I would like to know why it tends to an acid pH.
Pd: i did the calibration of the phmeter right before
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ChenBeier
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Post by ChenBeier »

Probably the NaCl is not clean. It contain some impurities which degrease the pH. NaCl is normaly neutral and doesnt change the pH.
Ssanchez11
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Post by Ssanchez11 »

Okay thank you, could it also be due to the water, cause i repeated it with MgCl2 and Kcl and both also showed a decreasal in the ph
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ChenBeier
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Post by ChenBeier »

What kind of water do you use?
Ssanchez11
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Conductivity

Post by Ssanchez11 »

Sorry for taking so much time to answer, i finally solved that problem
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ChenBeier
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Post by ChenBeier »

It would be nice, that you tell us what was the problem.
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