1 00:00:00,000 --> 00:00:01,340 2 00:00:01,340 --> 00:00:03,889 We've seen a reasonable number of acid 3 00:00:03,890 --> 00:00:05,390 reactions and base reactions. 4 00:00:05,389 --> 00:00:08,160 So let's just write down a few of them for review and let's 5 00:00:08,160 --> 00:00:10,449 see if we can see a general pattern here. 6 00:00:10,449 --> 00:00:12,629 And a lot of this might not be any news to you. 7 00:00:12,630 --> 00:00:16,990 So if we have hydrogen flouride, or if it's in an 8 00:00:16,989 --> 00:00:21,109 aqueous solution it's hydrofluoric acid. 9 00:00:21,109 --> 00:00:24,320 We know that this is a weak acid-- it doesn't disassociate 10 00:00:24,320 --> 00:00:24,850 completely. 11 00:00:24,850 --> 00:00:26,929 So it's in equilibrium. 12 00:00:26,929 --> 00:00:28,089 Some type of equilibrium. 13 00:00:28,089 --> 00:00:30,859 That doesn't mean the concentrations are equal. 14 00:00:30,859 --> 00:00:32,109 This hydrogen disassociates. 15 00:00:32,109 --> 00:00:35,609 16 00:00:35,609 --> 00:00:38,079 Actually, we know in reality, it tags a ride along with 17 00:00:38,079 --> 00:00:40,699 another water molecule and forms hydronium. 18 00:00:40,700 --> 00:00:44,760 And then you have-- and, of course, this is still aqueous. 19 00:00:44,759 --> 00:00:47,329 Everything is going on inside water. 20 00:00:47,329 --> 00:00:53,089 And then you have left over your fluoride anion, or 21 00:00:53,090 --> 00:00:53,940 negative ion. 22 00:00:53,939 --> 00:00:57,649 And that's also in an aqueous solution. 23 00:00:57,649 --> 00:01:00,000 And we could have rewritten-- actually, let me write another 24 00:01:00,000 --> 00:01:02,210 reaction here, just so you can see the general pattern. 25 00:01:02,210 --> 00:01:05,500 Let me write another acidic reaction. 26 00:01:05,500 --> 00:01:08,719 Let me write ammonium. 27 00:01:08,719 --> 00:01:16,819 So that's NH4 plus-- it's ammonia with an extra hydrogen 28 00:01:16,819 --> 00:01:22,599 in an-- let me just write that-- in an aqueous solution. 29 00:01:22,599 --> 00:01:29,399 That can disassociate to one of those hydrogens popping off 30 00:01:29,400 --> 00:01:31,790 in an aqueous solution. 31 00:01:31,790 --> 00:01:37,120 And then you have ammonia, NH3. 32 00:01:37,120 --> 00:01:39,189 That's also in an aqueous solution. 33 00:01:39,189 --> 00:01:42,480 Now both of these describe an equilibrium reaction, but it 34 00:01:42,480 --> 00:01:45,109 kind of implies that we're dealing with weak acids. 35 00:01:45,109 --> 00:01:48,359 You take an acid, and they're producing hydrogen, which is 36 00:01:48,359 --> 00:01:50,700 at least the Arrhenius definition of an acid if you 37 00:01:50,700 --> 00:01:53,560 looked at the Bronsted-Lowry definition where they're 38 00:01:53,560 --> 00:01:55,920 donating protons to the solution. 39 00:01:55,920 --> 00:01:58,409 They're creating hyrdonium, they're donating protons to 40 00:01:58,409 --> 00:01:59,179 the water around it. 41 00:01:59,180 --> 00:02:02,330 But it kind of describes it as an acid. 42 00:02:02,329 --> 00:02:04,939 But we know it's a weak acid, so this reaction goes in two 43 00:02:04,939 --> 00:02:05,370 directions. 44 00:02:05,370 --> 00:02:08,310 So we can write the same reaction essentially as a 45 00:02:08,310 --> 00:02:10,050 basic reaction. 46 00:02:10,050 --> 00:02:13,550 So we can-- instead of saying hydrofluoric acid is our 47 00:02:13,550 --> 00:02:17,790 acid-- we could say hey, if I just have a fluoride anion, if 48 00:02:17,789 --> 00:02:22,139 I just have a negative fluoride here, I could say a 49 00:02:22,139 --> 00:02:27,429 negative fluoride, if I put that in-- actually, I keep 50 00:02:27,430 --> 00:02:30,370 making that same mistake. 51 00:02:30,370 --> 00:02:33,289 The fluorine does not have an l in it. 52 00:02:33,289 --> 00:02:35,519 I do that because chloride does. 53 00:02:35,520 --> 00:02:38,689 Let me erase this. 54 00:02:38,689 --> 00:02:40,859 Hydrogen fluoride is HF. 55 00:02:40,860 --> 00:02:41,830 So it's just F there. 56 00:02:41,830 --> 00:02:43,440 Let me go to the periodic table. 57 00:02:43,439 --> 00:02:46,909 See, I always confused fluorine with chlorine because 58 00:02:46,909 --> 00:02:48,490 F is just for flourine. 59 00:02:48,490 --> 00:02:49,780 But you get the point. 60 00:02:49,780 --> 00:02:50,090 OK. 61 00:02:50,090 --> 00:02:55,259 So I could rewrite the same weak acid equilibrium as a 62 00:02:55,259 --> 00:02:56,729 weak base equilibrium. 63 00:02:56,729 --> 00:03:01,149 Or I could say a negative fluorine anion in an aqueous 64 00:03:01,150 --> 00:03:06,610 solution is in equilibrium with-- and now we're saying 65 00:03:06,610 --> 00:03:09,810 I'm considering this a base, which means that it's going to 66 00:03:09,810 --> 00:03:11,800 increase the concentration of [UNINTELLIGIBLE]. 67 00:03:11,800 --> 00:03:14,310 So what this might want to do is it might want to grab some 68 00:03:14,310 --> 00:03:16,240 hydrogen from some of the water that's 69 00:03:16,240 --> 00:03:17,290 in the aqueous solution. 70 00:03:17,289 --> 00:03:25,120 So it grabs some hydrogen and becomes hydrogen flouride, or 71 00:03:25,120 --> 00:03:27,009 hydrofluoric acid. 72 00:03:27,009 --> 00:03:31,679 Let me do that in that magenta color. 73 00:03:31,680 --> 00:03:33,189 It's aqueous. 74 00:03:33,189 --> 00:03:35,210 And where did it get this hydrogen from? 75 00:03:35,210 --> 00:03:37,230 Well, it got it from one of the surrounding water 76 00:03:37,229 --> 00:03:39,419 molecules, which was H2O. 77 00:03:39,419 --> 00:03:41,539 Since it gave away one of the hydrogens now 78 00:03:41,539 --> 00:03:43,629 it's just OH minus. 79 00:03:43,629 --> 00:03:48,289 So the surrounding water molecule is OH minus aqueous. 80 00:03:48,289 --> 00:03:49,679 Now these might look different. 81 00:03:49,680 --> 00:03:53,750 82 00:03:53,750 --> 00:04:00,750 This is donating a hydrogen to the surrounding medium, and 83 00:04:00,750 --> 00:04:02,939 then you're left with just the fluorine molecule. 84 00:04:02,939 --> 00:04:06,979 Well, this is essentially creating a hydroxide molecule 85 00:04:06,979 --> 00:04:09,750 out of the surrounding medium so it looks basic, but if you 86 00:04:09,750 --> 00:04:12,389 think about it, these reactions are the same. 87 00:04:12,389 --> 00:04:15,019 I mean, you could have just gone in reverse direction. 88 00:04:15,020 --> 00:04:17,189 You could say, hey, this is going to react with some 89 00:04:17,189 --> 00:04:21,540 random hydronium molecule or some random, free-standing 90 00:04:21,540 --> 00:04:22,520 proton out there. 91 00:04:22,519 --> 00:04:25,729 And then it could form hydrogen fluoride, but we know 92 00:04:25,730 --> 00:04:28,020 that hydronium isn't just sitting everywhere, that 93 00:04:28,019 --> 00:04:30,569 whenever you take the reverse reaction, whenever you're 94 00:04:30,569 --> 00:04:33,500 going in this direction this doesn't have to grab this 95 00:04:33,500 --> 00:04:35,129 hydrogen from an H3O. 96 00:04:35,129 --> 00:04:36,839 It could grab it from an H2O. 97 00:04:36,839 --> 00:04:38,269 And then you would have this reaction. 98 00:04:38,269 --> 00:04:39,500 These are equivalent. 99 00:04:39,500 --> 00:04:46,250 And we could do the same thing here for ammonium and amonia. 100 00:04:46,250 --> 00:04:50,160 We could write ammonia as a base. 101 00:04:50,160 --> 00:04:56,000 NH3 is in equilibrium as a weak base with-- it can grab a 102 00:04:56,000 --> 00:05:02,459 hydrogen from its surrounding medium and become NH4 plus in 103 00:05:02,459 --> 00:05:03,919 an aqueous solution. 104 00:05:03,920 --> 00:05:07,009 And then it would have grabbed that hydrogen, probably from a 105 00:05:07,009 --> 00:05:10,430 water molecule because that's what's around it. 106 00:05:10,430 --> 00:05:13,230 And so that water molecule will become an OH minus. 107 00:05:13,230 --> 00:05:16,470 And so now this looks ammonia is a weak base. 108 00:05:16,470 --> 00:05:18,960 Ammonium is a weak acid. 109 00:05:18,959 --> 00:05:21,680 But these are equivalent reactions. 110 00:05:21,680 --> 00:05:24,470 Now, you're probably already seeing a relationship here. 111 00:05:24,470 --> 00:05:26,940 Ammonium is a weak acid. 112 00:05:26,939 --> 00:05:29,680 Ammonia is a weak base. 113 00:05:29,680 --> 00:05:31,569 And what's the difference between the two? 114 00:05:31,569 --> 00:05:33,810 Just an H. 115 00:05:33,810 --> 00:05:39,759 Hydrofluoric acid is a weak acid, just a fluorine anion. 116 00:05:39,759 --> 00:05:42,089 A negative fluorine is a weak base. 117 00:05:42,089 --> 00:05:43,579 And what's the difference between the two? 118 00:05:43,579 --> 00:05:45,870 They're just difference of a hydrogen. 119 00:05:45,870 --> 00:05:48,879 Let me write that down. 120 00:05:48,879 --> 00:05:50,129 So let me write weak acid. 121 00:05:50,129 --> 00:05:53,399 122 00:05:53,399 --> 00:05:55,234 And then you have your weak base. 123 00:05:55,235 --> 00:05:59,410 124 00:05:59,410 --> 00:06:03,150 So your weak base-- let me write our weak acid is first. 125 00:06:03,149 --> 00:06:08,750 We had hydrofluoric acid, and then the weak base is when you 126 00:06:08,750 --> 00:06:10,930 essentially just dump the hydrogen, just 127 00:06:10,930 --> 00:06:12,319 the hydrogen proton. 128 00:06:12,319 --> 00:06:14,480 You kept the electron, so that's why it's a negative 129 00:06:14,480 --> 00:06:15,879 charge right there. 130 00:06:15,879 --> 00:06:18,180 Hydrogen without its one electron is just a proton 131 00:06:18,180 --> 00:06:20,009 because it has no neutrons. 132 00:06:20,009 --> 00:06:26,500 The other one was NH4 plus. 133 00:06:26,500 --> 00:06:31,149 You dump one of the hydrogens and you get NH3. 134 00:06:31,149 --> 00:06:33,199 So what's the difference going on? 135 00:06:33,199 --> 00:06:35,159 These are all minus a hydrogen. 136 00:06:35,160 --> 00:06:38,700 Or if you go this way, you're plus a hydrogen. 137 00:06:38,699 --> 00:06:42,399 So you have these kind of conjugates. 138 00:06:42,399 --> 00:06:45,799 And this has all been a long-winded way of introducing 139 00:06:45,800 --> 00:06:50,020 you to this idea that you have these conjugate pairs. 140 00:06:50,019 --> 00:06:53,229 Like hydrofluoric acid, or hydrogen fluoride and just the 141 00:06:53,230 --> 00:06:54,960 fluorine anions. 142 00:06:54,959 --> 00:06:56,674 So these are conjugate pairs. 143 00:06:56,675 --> 00:07:04,790 144 00:07:04,790 --> 00:07:08,960 Which are essentially two molecules that are identical 145 00:07:08,959 --> 00:07:12,069 except for a difference in one hydrogen. 146 00:07:12,069 --> 00:07:13,860 No more than one hydrogen. 147 00:07:13,860 --> 00:07:15,720 One day there might be a test where someone shows you two 148 00:07:15,720 --> 00:07:19,070 molecules that are separated by two hydrogens-- those would 149 00:07:19,069 --> 00:07:21,939 not be conjugate pairs. 150 00:07:21,939 --> 00:07:28,980 For example, if I show you H2O and OH minus, these are 151 00:07:28,980 --> 00:07:30,220 conjugate pairs. 152 00:07:30,220 --> 00:07:34,660 Because this over here is exactly this minus a proton. 153 00:07:34,660 --> 00:07:37,500 And, in fact, let me be clear that it's not just minus the 154 00:07:37,500 --> 00:07:39,850 hydrogen-- minus the proton. 155 00:07:39,850 --> 00:07:41,629 One of them is keeping the electron. 156 00:07:41,629 --> 00:07:46,149 So this is minus a hydrogen proton, this is plus a 157 00:07:46,149 --> 00:07:47,159 hydrogen proton. 158 00:07:47,160 --> 00:07:48,420 So the difference between these two are 159 00:07:48,420 --> 00:07:50,319 just a hydrogen proton. 160 00:07:50,319 --> 00:07:51,730 So these are conjugate pairs. 161 00:07:51,730 --> 00:07:58,410 Now, if I were to say that H3O and OH minus, you might be 162 00:07:58,410 --> 00:08:01,580 tempted to say, hey, this is very acidic, this is a base, 163 00:08:01,579 --> 00:08:02,719 this is a conjugate pair. 164 00:08:02,720 --> 00:08:07,630 But no, there's a 2 H, 2 proton difference. 165 00:08:07,629 --> 00:08:09,159 This is H3O plus. 166 00:08:09,160 --> 00:08:10,980 There's a 2 proton difference, so these are 167 00:08:10,980 --> 00:08:12,814 not conjugate pairs. 168 00:08:12,814 --> 00:08:18,949 169 00:08:18,949 --> 00:08:20,409 So let me just cross that out. 170 00:08:20,410 --> 00:08:21,510 But these are. 171 00:08:21,509 --> 00:08:25,199 Now, you could say, if you have H3O, you might say, hey, 172 00:08:25,199 --> 00:08:28,649 what's the conjugate base-- and that's a new word I just 173 00:08:28,649 --> 00:08:32,350 introduced you to-- what's the conjugate base for H3O if H3O 174 00:08:32,350 --> 00:08:33,178 is an acid? 175 00:08:33,178 --> 00:08:38,079 Well, you take one H from it and you get H2O. 176 00:08:38,080 --> 00:08:41,509 So this is a conjugate pair. 177 00:08:41,509 --> 00:08:44,149 And I just said a word without defining it, so now 178 00:08:44,149 --> 00:08:45,049 let me define it. 179 00:08:45,049 --> 00:08:49,049 Within every conjugate pair you have an acid and a base. 180 00:08:49,049 --> 00:08:51,740 And if you say, oh, what is the conjugate base for 181 00:08:51,740 --> 00:08:55,580 hydrofluoric acid, you get rid of a hydrogen and you say, oh, 182 00:08:55,580 --> 00:08:59,350 it's just this fluorine anion. 183 00:08:59,350 --> 00:09:03,759 If you said, I have some of ammonia, as a base, what is 184 00:09:03,759 --> 00:09:05,309 its conjugate acid? 185 00:09:05,309 --> 00:09:08,349 So if someone asks you, what is a conjugate acid, you add a 186 00:09:08,350 --> 00:09:12,980 hydrogen proton to it and you get ammonium. 187 00:09:12,980 --> 00:09:17,279 So I could call these the conjugate acid. 188 00:09:17,279 --> 00:09:19,589 Let me just change terminology-- conjugate. 189 00:09:19,590 --> 00:09:22,129 And we'll see that actually, you don't have to be using a 190 00:09:22,129 --> 00:09:24,149 weak acid or a weak base. 191 00:09:24,149 --> 00:09:31,069 Conjugate acid, and then you have a conjugate base. 192 00:09:31,070 --> 00:09:34,440 And even though something might be a conjugate acid or 193 00:09:34,440 --> 00:09:38,340 conjugate base, it doesn't necessarily mean that they're 194 00:09:38,340 --> 00:09:41,740 very basic, for example, or very acidic. 195 00:09:41,740 --> 00:09:45,870 If I have hydrogen chloride, we know this is a strong acid. 196 00:09:45,870 --> 00:09:48,990 Hydrogen chloride. 197 00:09:48,990 --> 00:09:52,460 Its conjugate base, we essentially just get rid of 198 00:09:52,460 --> 00:09:55,090 one of these hydrogen protons-- it doesn't take its 199 00:09:55,090 --> 00:09:56,480 electron with it. 200 00:09:56,480 --> 00:10:00,720 So it's just going to be the chlorine negative ion. 201 00:10:00,720 --> 00:10:02,300 This is its conjugate. 202 00:10:02,299 --> 00:10:04,279 If I gave you a chlorine negative ion and said, what's 203 00:10:04,279 --> 00:10:07,639 its conjugate base-- what's its conjugate acid? you'd say 204 00:10:07,639 --> 00:10:08,879 it's hydrochloric acid. 205 00:10:08,879 --> 00:10:11,590 If I gave you hydrochloric acid and I say, what's its 206 00:10:11,590 --> 00:10:15,300 conjugate base, you get rid of a hydrogen proton only, and 207 00:10:15,299 --> 00:10:18,099 you're left with the chlorine negative ion-- You said that 208 00:10:18,100 --> 00:10:19,279 its conjugate base. 209 00:10:19,279 --> 00:10:22,409 Now, with that said, we know that when you put hydrochloric 210 00:10:22,409 --> 00:10:25,189 acid, we know this reaction. 211 00:10:25,190 --> 00:10:28,000 This was I think the first reaction we looked at in 212 00:10:28,000 --> 00:10:29,779 aqueous solution. 213 00:10:29,779 --> 00:10:37,139 It disassociates completely to form hydrogen protons plus 214 00:10:37,139 --> 00:10:39,230 chlorine anions-- everything, of course, 215 00:10:39,230 --> 00:10:41,840 in an aqueous solution. 216 00:10:41,840 --> 00:10:43,899 Now, the fact that it disassociates completely, that 217 00:10:43,899 --> 00:10:47,699 this is not an equilibrium reaction, this implies that 218 00:10:47,700 --> 00:10:52,170 this guy is more basic than water. 219 00:10:52,169 --> 00:10:55,629 He has no temptation-- no, no-- let me say that he is 220 00:10:55,629 --> 00:10:57,230 less basic than water. 221 00:10:57,230 --> 00:11:03,710 He has no temptation to grab these hydrogen protons from 222 00:11:03,710 --> 00:11:07,710 the surrounding medium to reform hydrochloric acid. 223 00:11:07,710 --> 00:11:11,150 This reaction does not go in this direction. 224 00:11:11,149 --> 00:11:14,990 So even though this chlorine anion, or negative ion of 225 00:11:14,990 --> 00:11:24,560 chlorine, is a quote unquote conjugate base of HCL, that 226 00:11:24,559 --> 00:11:26,789 doesn't necessarily mean it's that basic. 227 00:11:26,789 --> 00:11:28,980 This is less basic than water. 228 00:11:28,980 --> 00:11:32,139 It wants the hydrogen protons less 229 00:11:32,139 --> 00:11:34,179 than, let's say, hydronium. 230 00:11:34,179 --> 00:11:39,889 So if you put some chlorine plus some hydronium, or let's 231 00:11:39,889 --> 00:11:43,879 say you have some H plus, you're not going to reform 232 00:11:43,879 --> 00:11:45,250 hydrochloric acid. 233 00:11:45,250 --> 00:11:50,259 So this is not really basic even though it's considered a 234 00:11:50,259 --> 00:11:52,620 conjugate base. 235 00:11:52,620 --> 00:11:54,759 And that's generally the case whenever you're dealing with 236 00:11:54,759 --> 00:11:58,919 strong acids, like in the case of hydrochloric acid. 237 00:11:58,919 --> 00:12:05,610 If I had a big solution of just chlorine anions in water, 238 00:12:05,610 --> 00:12:08,550 so I just had tons of a super high concentration of chlorine 239 00:12:08,549 --> 00:12:12,419 anions and water, because it's not going to do anything to 240 00:12:12,419 --> 00:12:16,549 change the actual hydrogen or hydroxide concentration in the 241 00:12:16,549 --> 00:12:22,509 water because it's less basic than the water itself-- it 242 00:12:22,509 --> 00:12:26,049 doesn't want to take or give anything to the water-- the 243 00:12:26,049 --> 00:12:30,379 PH, so if you have a soup, the PH would be 7. 244 00:12:30,379 --> 00:12:34,730 If you have chlorine minus in an aqueous solution-- and I 245 00:12:34,730 --> 00:12:38,440 don't care what its concentration is, you could 246 00:12:38,440 --> 00:12:41,480 have 10 molar of it-- the PH is still going to be 7 because 247 00:12:41,480 --> 00:12:43,700 it's not going to change its solution. 248 00:12:43,700 --> 00:12:46,640 It's not going to change the PH, just this by itself. 249 00:12:46,639 --> 00:12:48,970 Obviously, if you put hydrochloric acid in an 250 00:12:48,970 --> 00:12:51,399 aqueous solution this will change it, because you're 251 00:12:51,399 --> 00:12:54,389 going to be dumping all of these hydrogen protons into 252 00:12:54,389 --> 00:12:55,419 the solution. 253 00:12:55,419 --> 00:12:58,309 So in general-- I mean, you can kind of remember it, but I 254 00:12:58,309 --> 00:13:05,079 think it's maybe common sense-- a strong acid's 255 00:13:05,080 --> 00:13:10,940 conjugate base is neutral in water. 256 00:13:10,940 --> 00:13:12,160 Neutral. 257 00:13:12,159 --> 00:13:14,559 So that means no impact on PH. 258 00:13:14,559 --> 00:13:21,669 259 00:13:21,669 --> 00:13:27,399 You say chlorine plus H2O, I mean, you're essentially still 260 00:13:27,399 --> 00:13:29,519 going to have chlorine plus H2O. 261 00:13:29,519 --> 00:13:31,759 You're not really changing the concentration. 262 00:13:31,759 --> 00:13:35,480 Now, on the other hand, when you're dealing with weak 263 00:13:35,480 --> 00:13:38,960 acids, so this reaction will go in the other direction. 264 00:13:38,960 --> 00:13:44,690 If you put some fluorine in water, it will grab some 265 00:13:44,690 --> 00:13:47,710 hydrogen-- not necessarily a ton of it, but it will grab 266 00:13:47,710 --> 00:13:49,910 some hydrogen from the surrounding water-- and 267 00:13:49,909 --> 00:13:52,469 increase the hydroxide concentration. 268 00:13:52,470 --> 00:13:54,500 It's increasing the concentration of this thing 269 00:13:54,500 --> 00:13:55,220 right here. 270 00:13:55,220 --> 00:13:57,990 So it is making, in this case, it is making the 271 00:13:57,990 --> 00:14:01,129 solution more basic. 272 00:14:01,129 --> 00:14:04,029 It's increasing the PH of the solution. 273 00:14:04,029 --> 00:14:18,610 So whenever you have a weak acid its conjugate base will 274 00:14:18,610 --> 00:14:19,860 be a weak base. 275 00:14:19,860 --> 00:14:22,220 276 00:14:22,220 --> 00:14:23,430 And you could make this statement 277 00:14:23,429 --> 00:14:24,559 the other way around. 278 00:14:24,559 --> 00:14:27,949 If you have a conjugate-- let me switch colors, this is 279 00:14:27,950 --> 00:14:36,710 getting annoying-- conjugate base-- sorry, a weak base, its 280 00:14:36,710 --> 00:14:40,560 conjugate acid is going to be a weak acid. 281 00:14:40,559 --> 00:14:42,449 So hopefully you get the idea here. 282 00:14:42,450 --> 00:14:44,650 It's actually not that fancy of an idea. 283 00:14:44,649 --> 00:14:48,860 It's just that if you have an acid, its conjugate base is 284 00:14:48,860 --> 00:14:50,534 just that acid minus a hydrogen. 285 00:14:50,534 --> 00:14:53,059 286 00:14:53,059 --> 00:14:57,219 If you have a base, its conjugate acid is just that 287 00:14:57,220 --> 00:14:59,410 thing plus a hydrogen. 288 00:14:59,409 --> 00:15:05,439 Actually, let me just do a bunch of problems here just to 289 00:15:05,440 --> 00:15:10,640 really hit the point home of what we're talking about. 290 00:15:10,639 --> 00:15:11,809 Let's just do a bunch of them. 291 00:15:11,809 --> 00:15:19,939 So if this is the acid and this is its conjugate base, so 292 00:15:19,940 --> 00:15:24,010 if I have-- I mean, you don't even have to know the words. 293 00:15:24,009 --> 00:15:26,129 If I have that, the conjugate base, well, I'm just going to 294 00:15:26,129 --> 00:15:28,269 get rid of a hydrogen proton. 295 00:15:28,269 --> 00:15:30,299 So NO3 minus. 296 00:15:30,299 --> 00:15:32,620 I didn't get rid of the whole neutral hydrogen molecule. 297 00:15:32,620 --> 00:15:34,950 Remember, I just took a proton away, the electrons stay the 298 00:15:34,950 --> 00:15:38,360 same, so I have a negative charge. 299 00:15:38,360 --> 00:15:43,460 Let's say we did H2SO4. 300 00:15:43,460 --> 00:15:46,889 So its conjugate base, get rid of a hydrogen. 301 00:15:46,889 --> 00:15:49,759 HSO4 minus. 302 00:15:49,759 --> 00:15:55,439 If I have hydrogen bromide, get rid of a hydrogen. 303 00:15:55,440 --> 00:15:57,420 It's BR minus. 304 00:15:57,419 --> 00:16:00,149 And this is a strong acid. 305 00:16:00,149 --> 00:16:03,009 So this is going to be a neutral-- if you put this in 306 00:16:03,009 --> 00:16:05,439 water, it's really not going to do anything even though you 307 00:16:05,440 --> 00:16:08,720 are calling it hydrogen bromide's conjugate base. 308 00:16:08,720 --> 00:16:10,460 Now, if we go the other way. 309 00:16:10,460 --> 00:16:13,420 If we give you the base, if I give you OH minus, what's its 310 00:16:13,419 --> 00:16:14,569 conjugate acid? 311 00:16:14,570 --> 00:16:18,320 Well, you add a proton to it, you get H2O. 312 00:16:18,320 --> 00:16:22,090 If I have H2O-- we already did that-- you add a proton to it, 313 00:16:22,090 --> 00:16:24,410 you get H3O plus. 314 00:16:24,409 --> 00:16:28,539 If you have-- I mean, we could just keep going. 315 00:16:28,539 --> 00:16:29,879 Let's say I have that. 316 00:16:29,879 --> 00:16:32,090 If I add a hydrogen to it, I have H2. 317 00:16:32,090 --> 00:16:34,850 318 00:16:34,850 --> 00:16:35,639 There you go. 319 00:16:35,639 --> 00:16:37,549 And it's neutral now because I added a proton. 320 00:16:37,549 --> 00:16:40,639 Anyway, hopefully I haven't beaten this horse to death and 321 00:16:40,639 --> 00:16:45,519 you understand what conjugate acid and bases are all about.