Consider the following acid-neutralization reactions involving
the strong base NaOH(aq):
HNO31aq2 + NaOH1aq2¡NaNO31aq2 + H2O1l2
HCl1aq2 + NaOH1aq2¡NaCl1aq2 + H2O1l2
NH4+1aq2 + NaOH1aq2¡NH31aq2 + Na+1aq2 + H2O1l2
(d) In the third equation NH4
+1aq2 is acting as an acid. Based
on the value of H° for this reaction, do you think it is a
strong or a weak acid? Explain.

Question

Accepted Answer

Hello. Everyone in this video we have these three given reactions and were given also the envelop of neutralization. For each. I'm trying to see if this H. C. N. Is going to be a weak or strong acid. So the first thing that we notice is that H C. N. Is here and that's going to be what we're interested in. So interested. And of course we also have the assets of Hcl and CH three C H. Well, one thing that I noticed is that Hcl is a known strong acid and if we know that this is strong acid we can compare this directly to this. This one is not a known acid but it is a weak acid. But just knowing that we have a strong asset here, we can directly compare this with this. So we kind of just ignore this in this problem. All right. And so we go ahead and compare like I said, the Hcl and the HCM. So we're basically comparing the and the pay of neutralization that the problem provides. And we know the greater the anthem p information. The stronger the acid draw this arrow a little bit better. They're stronger the acid. Alright, so we're comparing here the answer api of for our neutralization. I apologize of neutral realization. All right. So the delta H. Of the H. C. L. So the known strong acid That's going to be negative 57.9 killer jules Permal and as our asset of interest. The H. C. N. That has a delta H equal to -12.13 kila jules per so like we said, they created the entire view of neutralization, the stronger the acid as you can see, this value is a lot greater comparing this value right here. And because this value is greater, we know that this is a stronger asset and therefore this is significantly lower. So it's a significantly less strong are more weak acid. So just by doing this comparison of the envelop of neutralization, we know that the hcl is a strong acid and that the H C. N. Is going to be a weak acid. So our final answer, it's going to be that the H C N. Yes, a week acid. And this is going to be my final answer for this question. Thank you all so much for watching.

Verified Solution

Key Concepts

Acid-Base Theory

Strength of Acids

Enthalpy Change (ΔH°)