Hi there Holly,
I stumbled upon your website while doing a bit of research and thought that maybe you would be nice enough to answer a question for me. I'm not a chemistry student or a student of the like; I am actually an esthetician student. I am constantly on the internet doing research about topics that I learn in my classes because my teachers and my books don't go in any depth on most subjects. I digress...
My question is- Is a solution of baking soda and water considered an electronegative solution?
I don't have enough chemistry background to figure it out on my own! We are learning iontophoresis using galvanic current as a modality, and I want to make sure that I understand it completely before I get out there working on faces! : )
Thanks in advance for reading my email. I thoroughly enjoyed reading your web page.
Thanks for your question! I've been asked questions like this before, so you are not alone.
Well, I am afraid there is no such thing as an "electronegative solution". It doesn't make sense.
"Electronegative" is an adjective, a numerical value applied to an atom: some atoms are more electronegative than others. The term isn't applied to other items, like liquids or solutions or compounds or molecules (which are made of more than one atom.)
But it is a term I often see misused by my students, they will often describe something as "electronegative" when you can only describe an atom as being electronegative. Usually we discuss one atom as being more electronegative than another.
Thanks to Linus Pauling, each atom has an electronegativity value assigned to it; you can look up tables of their electronegativities on the internet. The values range from close to 0, to 4,which is the highest (that's the fluorine atom.)
It's such a useful value that I salute Linus Pauling every single time I think about electronegativity, which is constantly.
Electronegativity is something I jokingly call "electron hungry-ness", just to help my students remember what it means. But technically, it means the ability of an atom to pull on electrons through a bond to another atom.
First you have to know that electrons, which are negatively charged particles, can form the glue or "bond" that joins one atom to another.
If two atoms with different electronegativaties bond, the more electronegative one pulls electrons slightly away from the less electronegative one (here you have to start picturing electrons less as particles and more as a sort of slushy negative stuff flowing between the two atoms) and the bond becomes "polar". Polar means having a negative end and a positive end. Polar things act like little magnets, so a polar bond acts differently than one that has the same charge on both sides (a nonpolar one), and that allows us to make predictions about how that bond will behave.
But perhaps you are thinking of just "negative", as in negatively charged?
A solution of baking soda in water is basic, also called alkaline. A basic solution is one that has an excess of a certain molecule in it which is derived from water, called the hydroxide ion. The hydroxide ion has a negative charge, so perhaps that is what you are thinking of? The hydroxide ion is formed when water loses one hydrogen, and that hydrogen leaves its electron behind on the remaining piece, making it negative (because electrons are negative.) The hydroxide ion is represented like this: OH-
Even a very concentrated baking soda solution will not be horribly basic, however, because the base in it (bicarbonate) is only weakly capable of pulling hydrogens off water. So we say that baking soda, (or the bicarbonate ion in it) is a weak base, not a strong one.
The opposite of a basic solution is an acidic one: an acidic solution has an excess of hydrogen ions, that is, hydrogens that are missing one electron. They are represented like this: H+
I am sure the reason you are using baking soda is to allow the water to carry a charge. Electricity is simple; it is just moving charge. But water does not conduct electricity!
A lot of people think water conducts electricity, but it does not. Water molecules have no net charge, so if you had completely pure water (like distilled water), you can stick a charge (positive or negative, whatever you like) in it and the charge just gets stuck, it can't go anywhere. The charge can't be carried away, and the water won't "conduct" it.
If you want water to carry the charge, you have to add charged particles that can travel through the water. Positively charged particles will travel from a positive charge to a negative one, and negatively charged particles are attracted to a positive charge source. Either way, you get a flow of charge, known as a "current".
The baking soda solution has baking soda, which is sodium bicarbonate. As soon as the sodium bicarbonate hits the water, it falls apart into two charged pieces, the sodium ion, which is positively charged (Na+), and the bicarbonate ion, which is a group of atoms that collectively have a negative charge (HCO3-). The presence of these charged particles, called ions, allows the current to flow. It would probably also work if you added table salt, which also contains ions.
I don't know if that hit anywhere near answering your question, but I hope it helped!