Hi, first off thanks for taking time to look at my questions!
Ah I didn't know that. So between the CH3Ch2 fragment and the CH2CHO fragment, the former would just occur more often. Is this always the case in terms of Hydrocarbon fragments vs. fragments cont. C, H, and O ?
In general, you will see alpha cleavage more often than many other types of fragmentation (such as loss of a methyl).
The second one was Li+(g) + F-(g) --> LiF(s)
If the reaction were Li(g) + F(g) --> LiF(s), then I would agree with your answer. However, in this case you aren't looking at the ability of the metal to lose electrons and the ability of the non-metal to gain electrons. Since we're dealing with Li+
the metal has already lost an electron and the F-
has already gained an electron.
Here, what we are comparing is the stability gained from bringing a positive charge and a negative charge together. Now, the stability gained from bringing cations and anions together (the Coulombic potential) is related to two things: 1) the charge of the anions and cations, and 2) the distance between the cations and anions.
When comparing NaCl to LiF, the charges are the same since both contain a +1 cation and a -1 anion. Therefore, the difference must be due to the distance between the anion and cation. Given this information, can you explain why reaction (b) is more exothermic than reaction (d)?
Ah I see that that would indeed lead to the formatnion of sodium ethanoate. What's the line that determines when we're adding too much NaOH though? (I understand that III doesn't work because you'd have too many OH ions in sol'n but when does it cross the line? I suppose we need the ka value of ethanoic acid then?)
It depends on the concentration of the acetic acid (ethanoic acid) in solution (i.e. the buffer capacity). Here's an exercise for you: calculate the amounts of ethanoic acid and the amounts of sodium ethanoate in solution when you add 25mL of the NaOH solution versus when you add 50mL of the NaOH solution.
Here would be another calculation that you could try. In order for a buffer to be effective, the ratio of conjugate acid to conjugate base should be between 1:10 and 10:1 (approximately). What are the minimum and maximum volumes of NaOH that you could add to your solution from question 3 and still have a effective buffer?