00:01
So here we're dealing with hcn, reacting with water, in other words, acting as an acid to become h3o plus and the cyanide ion, cn minus.
00:12
And so we can look up the ka value that governs this reaction.
00:18
In other words, it describes how far the equilibrium goes, and that's 6 .17 times tenths than negative tenth.
00:24
And so now we're going to perform our traditional ice table like work here this is something you should be really comfortable with by now but if you're not you can go back to some of the earlier videos i think questions like 64 65 i go over this in detail but the ka is going to equal x squared over our initial concentration 0 .125 minus x where x is equal to the concentration of h3o plus now x is going to be much smaller than 0 .125 so we'll ignore this value.
00:56
It's basically has no effect on the denominator.
00:59
And so we can solve for x, which, like i said, equals our concentration of h3o plus.
01:04
And that is equal to 0 .878 times 10 to negative 6 molar.
01:12
8 .78, pardon me.
01:15
And so now to think about what we're being asked.
01:20
The percent ionization is the amount from our initial acid hcn that went and became h30 plus.
01:31
Basically we're asking how much happened, you know? and so the percent association that we're going to be looking for is going to take this amount, the concentration of h3o plus...