So this is basically what you need to carry out this experiment:
You need; a stannous chloride solution, a dish to hold it in, some alligator clips,
some paper clips and a power source.
Each of the paper clips will serve as an electrode, and they're clamped to either
side of the dish using the alligator clips.
The dishes then filled with a few milliliters of two molar stannous
chloride solution (~3 mL 2M SnCl₂) which I made in a previous video. I'll provide a link to
the stannous chloride video in the description.
Then to the power source, an alligator clip is attached to the positive and the
negative terminals. The moment the circuit is completed by connecting the
second alligator clip, the crystals should start to grow.
The crystals will grow from whichever alligator clip was attached to the
negative terminal.
So, after [it] was attached we can see the crystal starting to grow. It was very
interesting for me to see this the first time but I was honestly quite
underwhelmed at how slow it was and how few crystals were growing.
I was very underwhelmed with the results, so I decided that I'm going to need to
use something with more current if I want to get the crystals to grow faster
and to get more of them.
The crystals are pretty small, flaky and fragile but if you like you can scoop
them up and collect them.
So I found an old power supply from a laptop I used to have.
I cut the end off and stripped away about an inch of the wire on the end.
The free copper wire that you see wrapped around the inner white wire is
generally the negative or the ground. So it was removed from the white wire and
twisted up a little. Then, with the white wire free a little bit of it was
stripped to expose the inner wire, which is the positive.
So now these are going to serve as our positive and negative terminals instead
of the battery.
And then just like before, we attach an alligator clip to each of the terminals.
In general, the wrapped wire is positive but depending on the polarity of your
adapter it could be negative. In the end, it doesn't really matter because it
doesn't really matter which side the crystals grow from.
And then, to get things going we plug it in.
So now when we use this much more powerful power supply, we can see that
the crystals are growing much faster than before.
However, due to the greatly increased power input it starts to heat up the solution
and you can see that the solution on the red side starts to actually boil a
little.
So what's happening here is known as a redox reaction.
Basically, what happens is that the tin ions are oxidized at one end and reduced
at another.
So, the stannous chloride starts off as tin 2 plus (Sn²⁺) but at one side receives
electrons and another it gives away [electrons].
At the positive side tin 2+ is giving away 2 electrons to form tin 4+ (Sn⁴⁺) and at
the negative side
it's receiving two electrons to form tin 0 or tin metal (Sn).
Just for fun, you can reverse the terminals so the tin grows from the other side and
you can see that the existing tin crystals start to shrink.
Because the solutions already been used extensively and it's pretty hot
the demonstration isn't the most beautiful thing ever.
But, in essence what we're seeing here is the tin metal is giving up two electrons
to form tin 2+ or tin 4+ which can be re-dissolve in the solution.
I opted to redo the experiment with better lighting and indoors, and the
result was much nicer. The crystals grew very nicely and I was quite satisfied
with the result. To end the video I'll let this play out in real time.
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