This is a continuation from my post of December, 2013 — it was getting sort of long for a post. As there, work safe, work with your parents, and take seriously the precautions on the bottles. Wear gloves, and goggles; don’t drink anything but food products (nothing with a skull and bones on the label). If stuff gets on you, wash it off fast. Experiment 1 appeared here; I continue from experiment 2.

2) A simple acid -base indicator. Grape-juice or wine will turn red when acidic, or blue when base is added. Turn a glass of grape juice bright red by adding some lemon juice. The color remains even when you add sugar or water because these are not acids or bases You’ll find the mix with sugar and lemon juice tastes good if you don’t use too much lemon juice. Drink it as a treat, note the sour taste– acids all taste sour (tangy). You can turn grape juice red using vitamin C or vinegar. In each case, the red grape juice will taste sourer, more tangy than regular grape juice. It will not taste good with vinegar, but will still be tangy. Alternately, you can add a little grape juice to homemade lemonade to make natural pink lemonade.

Now lets use some bases to return the blue color to the grape juice and get rid of the sour flavor. More-or-less the only safe base to use is baking soda. Add some to the red grape-juice in a glass, or to ordinary grape juice, but don’t stir yet. The grape juice will turn blue at the bottom of the glass where the baking soda settled. It may bubble as well, and turn blue along the path where the baking soda settled or where the majority of the bubbles rise. Now stir it to make the whole glass blue. If you drink it, the mix will be less tangy, less sour, a bit bitter. Bases taste bitter; acids sour. Wine makers aim for just the rich degree of acid. burgundy wines should thus have a burgundy color.

You can use this indicator to test chemicals in your house. Cement should be basic, plaster should be neutral (I think). Some soaps are acid, others basic. Some soils are acid, others basic. Ammonia from under your sink is basic, as is the crystal Drano, and a special brand of soap — ivory, the white soap that floats. Do not drink any of these mixtures as they are all toxic. In the olden days chemists used to drink things like this — and tended to die young. Don’t do the same. Use the color change of the grape juice instead of your tongue to tell if something is an acid or a base. YOu can also test acid base using the water left over from boiling purple cabbage. It’s probably the same chemical as found in grape juice; soak some paper towel into this juice — it is now called litmus paper and the test is called a litmus test. If you buy a high-end chemistry set, it will come with strips of litmus paper — paper that has been soaked in purple cabbage juice. Make your own instead.

3) Making hydrogen, chlorine, (or bromine) and sodium hydroxide. Hydrogen is useful as mentioned above (e.g. for balloons and fuel cells), and chlorine is a deadly gas used to kill soldiers in WWI. Currently, it is an important industrial chemical used to kill germs and to bleach clothes white. Do not breathe it; you will survive no better than the WWI GIs. Make chlorine outside only. A simple way to make chlorine is to put salt in water and pass an electrical current through it using a 6 V or 9 V battery and non-corrosive electrodes. Make your electrodes from carbon from a pencil, or solder (lead-tin or tin-antimony). Put the salt water in a glass, connect the battery to your two electrodes using from the two terminals, and put the ends of the lead or solder in the glass. If you did this right, you’ll see the same amount of bubbles from both electrodes, and you’ll smell a nasty smell.

How this works is as follows: when salt dissolves in the water, it turns into separate sodium and chloride ions: Na+ and Cl-.  Besides this, some of the water converts to hydrogen and hydroxide ions: H+ and OH- ions the +  – signs are because these ions are charged. (Old joke: one atom says to another, “I just lost an electron.” “Are you sure?” “I’m positive.”) Here is an equally bad chemistry joke.

When electricity goes through the solution, the positive ions are attracted to the negative electrode, and the negative ions to the positive electrode. At the negative electrode (the cathode) the positive hydrogen ions are reduced to neutral hydrogen gas (hydrogen ion is reduced rather than sodium ion because hydrogen ion is the easier one to reduce). At the other electrode chloride ion is oxidized to chlorine gas– chlorine ion is the easier to oxidize. The remaining sodium and hydroxide ions float separately until you boil off the water. At that point you get NaOH – lye. Lye is the main active component of Drano (experiment 1) this is how it is made; it’s called the chlor-alkali process (alkali is another name for lye). The hydrogen you make can be used to float a small balloon, or to fuel a fuel cell (perhaps you have one?). The chlorine gas is green and toxic; it’s heavier than air; let it go. You can take a brief whiff to tell which gas is which, but don’t breathe much — it’s toxic. Perhaps a safer route is to use plain copper wires for electrodes instead of pencil lead or solder. In that case the copper wire will corrode from the chlorine and the only gas you’ll get is hydrogen. The copper wires will turn green and dissolve as they change to copper-chloride, a green, soluble powder. If you like, save some of the copper chloride you make. You can electro-plate with it. It also kills unwanted plants.

4) Bromine is made the same way as chlorine, but you need a hard-to-get chemical: sodium bromide, NaBr. You just repeat the process above using solder or lead as electrodes and using the sodium bromide instead of sodium chloride, salt in the water (mix a tablespoon of NaBr into half a baby-food jar of water. When you’re done instead of green chlorine gas, you’ll get a brown, heavy liquid in bottom of the NaOH solution — that’s bromine. It’s an antiseptic and an octane enhancer, one that’s somewhat less -toxic than chlorine or lead. Bromine is sometimes used to kill bacteria in swimming pools.

5) Dissolve iron, zinc, and non-noble metals in a strong acid. The only strong acid you are likely to get in a hardware store is called muriatic acid. It is really hydrochloric acid, HCl, and is quite toxic and dangerous. As with Drano, it will dissolve you. It does not take much muriatic acid to change the color of your grape-juice. Don’t let it get in your eyes (wear goggles) or on your hands (wear gloves); if you do, wash it off fast, and Don’t drink it, even with grape juice. Muriatic acid is mostly used to clean algae off of cement. Buy a small bottle at the hardware store, and start by putting a small iron nail into it. You’ll see it bubbles releasing hydrogen. The reaction is Fe + 2 HCl –> H2 + FeCl2. The solution is yellowish. Take the nail out carefully (use gloves, or put your hands in a baggie), and save the solution in a glass bottle (a baby food jar, for example. Label the jar well “muriatic acid + iron, danger.” Add a skull and bones. You’ll want to save it for further experiments. When you’re done bottling you can give the mad scientist laugh.

Now cut a penny in half (use a newer penny — one with a silvery inside), and use those cool $3 scissors you can get at the hardware store — the ones that can cut a penny. Drop 1/2 the penny into the muriatic acid. It dissolves faster than the iron nail because the center of the penny is zinc, a metal that’s more active than iron (we’ll be doing more with zinc later). Stainless steel will not dissolve in this acid because the chrome and nickel in the steel makes it (sort-of) stainless. Aluminum will dissolve, but takes a while to get going (why?). You’ll be able to dissolve almost every metal except copper and gold in this acid. I suspect that you could dissolve copper if you add a few of the ammonium nitrate balls from the Drano. It is possible that some FeCl2 or CuCl2 would do the same, (you made this earlier); it certainly will in a basic, or neutral solution exposed to air (below). Gold is called a noble metal because it’s hard to dissolve. You can use strong acids to distinguish gold from brass.

Something to do with the FeCl2. FeCl2 is an etching chemical used to etch copper, for example. Get a sheet of copper at the hardware store and coat it with a thin layer of wax by holding it in the waxy soot of a wax candle. Now use a nail to scrape off the wax into the form of a drawing or picture. Leaving the rest of the wax in place. Mix up an etching solution of the FeCl2 you made before plus enough ammonia to make it slightly basic (here’s where your grape juice or litmus paper comes in handy). Apply the solution to your copper plate and let it sit for an hour. When you remove the wax, you’ll find the picture has been be etched into the copper plate. The plate is now “art”. Alternately, you can cover your plate with ink and use it to make many copies of your drawing. This is called publishing. The reaction, as I understand it, is 2 Cu + O2 (air) –> 2CuO; 2CuO + H2O+ FeCl2 –>Fe(OH)2 +CuCl2. Oxygen from the air is a key ingredient in making this reaction happen; it dissolves in the solution, reacts with the bare copper, and then is removed by the iron chloride to form insoluble iron hydroxide (rust), and soluble CuCl2 leaving the metal surface bare and open to oxidation. You can also dissolve aluminum foil with muriatic acid, but it takes a while to get going. Why? Did adding FeCl2 or CuCl2 help?

I’ll try to write more blog posts on this subject in a month or so. In the meantime, if you want to do more science, it helps to read science books. Try Mr Wizard, or any chemistry book at the library (ask for help). Read Isaac Asimov’s science books (or his science fiction), or any science book published by Golden Books. Learn math, and physics or practical stuff (engineering, biology). Good luck. And stay safe.

Robert Buxbaum, December 29, 2013. If you’ve got experiments you’d like to see me include, please send them along.