organic chemistry - Why is acetic acid more acidic than phenol?

Acetic acid (ethanoic acid, $\mathrm pK_\mathrm a \approx 5$) is more acidic than phenol ($\mathrm pK_\mathrm a \approx 10$), which is reflected in their reactivity with a weak base such as sodium carbonate (adding acetic acid leads to effervescence of carbon dioxide).

However, if we look at the structures of acetate and phenoxide ions, the delocalization of negative charge should be greater in the phenoxide ion as the charge moves inside the benzene ring. On the other hand, in the acetate ion, the negative charge is delocalized between two oxygen atoms only.

How is it possible that acetic acid is still a stronger acid, even when its conjugate base has fewer resonance structures?

Answer

There are actually several factors that affect the stabilization of negative charge. The first is what kind of atom centers the charge can be delocalized on and the second factor is how many atom centers the charge can be delocalized on. The first factor is more important than the second. Just think it like quality is more important than quantity. Symmetry is another factor but not very important in your case.

Let's look at the ethanoic acid vs phenol case. In the acetate ion, the negative charge is delocalized on two oxygen atom centers, while in the phenoxide ion, the charge is delocalized on one oxygen and three carbon atom centers. Because oxygen is much more electronegative than carbon, the delocalization of negative charge over two oxygens is better than delocalization over one oxygen and three carbons. Quality beats quantity here.

If you have 2,4,6-trichlorophenol, because the strong election withdrawing chlorine atoms is helping carbon center to stabilize negative charge, it is a much stronger acid than phenol itself. This is an example of the inductive effect at work, as opposed to resonance.

hiragana - Reading and significance of dakuten with kana for which it normally is not used

Came across these while reading a novel.

How do you read this?

Answer

The letter あ゛doesn't exist indeed in Japanese. But あ゛is rarely used in manga to emphasize the letter あ. The letter ゔ exists. But it is normally written in katakana.

Pronunciation: ゔぁ => va ゔぃ => vi ゔ => v or vu ゔぇ => ve ゔぉ => vo

halacha - Is one allowed to smoke Marijuana?

Not taking into account Dina D'malchusa, what are the Halachic problems with smoking marijuana? Is it allowed?

Answer

Igros Moshe has a tshuva regarding smoking Marijuana. He forbids it for several reasons:

1. It damages the body. Moreover, even if people claim that people are not harmed, their intellect is harmed, which is a worse damage than damaging the body. It prevents one from understanding Torah, Davening, and keeping mitzvos properly.


2. One gives himself extra cravings, worse than those for food and drink. This is a sin which we learn from the "Rebellious son", which is punished for his cravings for food, even though the food is one hundred percent kosher. All the more so it is forbidden to create within himself a new craving for something that he naturally has no desire and no need. Moreover, just like the reason that we execute a "Rebellious son" (even though he didn't do any sin worthy of execution) is that we see that he will come to robbing the population, so too drug use is a step towards robbery.


3. It is a lack of honoring one's parents, who are no doubt upset by the son's actions.



4. Kdoshim Tih'yoo (be holy) is a positive commandment. According to the Ramban, this commandment means not to be "disgusting with the Torah's permission".

He finishes off that it is a clear-cut prohibition, especially for b'nei y'shiva.

R' Adin Even-Yisrael (Steinsaltz) wrote what the Lubavitcher Rebbe told him in a private audience about drugs. He said that the whole point of the Torah is for one to be a master over himself. Drugs (as well as other addictive and psychoactive substances) make themselves the master over him.

Even though one could say that bread is also psychoactive, yet drugs are worse, as they are addictive. Once one is addicted, it's almost impossible to quit.

grammar - How to parse 中国人で日本語が話せる方は、お電話ください。

I have a difficulty to parse the following sentence.

中国人で日本語が話せる方は、お電話ください。

I just understood the following partial phrases.

• 中国人で means "with Chinese"


• 日本語が話せる方 means "person who can speak Japanese"


• お電話ください means "please telephone"

I have learnt で that functions as

• バイクで学校へ行きます。I go to school by a motorcycle.



• 家で食べます。 I eat at home.

But the particle で in question is difficult to understand.

What does the sentence actually mean and what is the usage of で in this case?

Answer

You are mixing up two completely different 「で's」.

1. 
   

   Particle 「で」← 「バイクで行く」、「家で食べる」, etc.

   
   



2. 
   

   [連用形]{れんようけい} (continuative form) of the affirmation auxiliary verb 「だ」. (Auxiliary verbs conjugate just as verbs and adjectives do.)

   
   

「[中国人]{ちゅうごくじん}で[日本語]{にほんご}が[話]{はな}せる[方]{かた}は、お[電話]{でんわ}ください。」

It is the second 「で」 above that is used in this sentence; therefore, 「中国人で」 does not mean "with Chinese".

「中国人で日本語が話せる方」 is a relative clause meaning "those who are Chinese and able to speak Japanese".

It uses 「中国人で」 instead of 「中国人だ」 because the phrase continues to add more information besides the applicants having to be Chinese.

The sentence means:

"Those who are Chinese and able to speak Japanese, please call (us)."

product recommendation - Sefer of Jewish Philosophy

Is there any Sefer which goes through the various philosophical issues according, and explains the opinion of the jewish philosophers? (Example what is space; according to the rambam, rasag... What is the soul according to .....)

hashkafah philosophy - What is in greater violation of the prohibition of blasphemy: Atheism vs Avoda Zara?

In the eyes of halacha, who is in greater violation of the prohibition of blasphemy, an idolator or an atheist?

Whichever is worse, is that the case by both Jew and Non-Jew?

minhag - People half-standing for אלקינו in zimun

When conducting a zimun with ten or more men, the nusach is to say "...ברוך אלקינו שאכלנו משלו".

I have noticed that many people, when saying the word "אלקינו", get up from their seats at least a little bit, similar to the respectful gesture many people do when the rav gets up to speak.

What is the reason (if there is one at all) for this practice, and what is its source?

Answer

It is said in name of Rav Chaim Soloveitchik that when we say Elokenu it makes the Zimun into a Davar Shebikedusha. That is the reason why some people stand when they say Elokenu, since according to some the Minhag is to stand during a Davar Shebikedusha. This Minhag is not universal. Sefardim do not stand by Kaddish in many cases.