This is an easy-peasy little experiment to post while bigger and better things progress. In theory (which I didn't even have to verify on the internet), I can make "table salt" by adding NaOH to HCl. I'm using 31% HCl and 100% NaOH so I am going for the big reaction.
HCl + NaOH -> H2O + NaCl
Basically, the ions switch partners... making simple water and salt from two extremes of the chemical world. Since 31% HCl is not fully disassociated, technically its pH is 0. Since I am using solid NaOH, its pH is 14.
This is a classic acid/base reaction where the H+ ions from the acid form with the OH- ions from the base to form water. The Na+ and Cl- ions happily bond in the aftermath.
See what happens when I drop one of the two grams of NaOH into the fuming HCl:
It gives a serious pop (and the solution heats quite rapidly). I should note dropping even a single grain smaller than a typical grain of sand into the solution makes a noticeable impact. Immediately the NaCl forms in the solution and falls to the bottom. It cannot dissolve in this concentrated solution.
I did not want to waste all of my NaOH to neutralize all of the acid, so when the leftover solution was removed, I did test the "salt" left behind. Here is a picture:
Sure enough it tasted like table salt and did not burn my tongue. Check. When I added water it immediate dissolved into a clear solution with no further drama.
It so happens I had ~3g of NaCl. It seems kind of magic to have more white solid than what I put in, but NaCl has a molecular weight of almost 150% that of NaOH. That is because the Cl ion weighs a little more than twice as much as the hydroxide ion (35.5 vs. 17.0 g/mol). This added weight is of course offset by reducing the density of the HCl in H2O solution.
This is a super simple and surprisingly pleasing experiment.
Thanks for reading,
Paul
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