Rank the following compounds in order of increasing acid strength (1 = weakest, 4 = strongest)
HCOOH
CH2ClCOOH
CHCl2COOH
CH3COOH
Can you look up the Ka for each acid? If so won't that tell you which is stronger? or are you supposed to do it some other way?
i cant find a Ka chart that includes all those, and also, i wasn't even any numbers whatsoever to work with!
http://members.aol.com/logan20/acid_str.html
Here is a site that explains acid strengths. It's a good bit of material to wade through BUT all of the possibilities are there. In this case, scroll down about 2/3 of the way to strenghts of oxy acid and a little further they talk about carboxylic acids. All of the acids you list are carboxylic acids. Then a paragraph or two later they talk about the effect of adding highly electronegative atoms (in this case Cl) and the effect on acidity. If you need more help just say the word. But I would go with CH3COOH, HCOOH, Cl......, and Cl2...... from weakest to strongest. I presume you are to use this kind of reasoning and not use Ka. However, if you wish I can look up the Ka for the acids. I know HCOOH is 1.7 x 10^-4 and acetic acid is 1.75 x 10^-5
Here is a table of Ka values.
(Broken Link Removed)
Do you know the names. formic, acetic, chloroacetic, dichloroacetic
To rank the compounds in order of increasing acid strength, we need to consider the factors that affect acid strength. The primary factor is the stability of the conjugate base. A more stable conjugate base indicates a stronger acid. Here's how you can determine the order of acid strength for the given compounds:
1. HCOOH (Formic acid): This compound has the formula RCOOH, where R is a hydrogen atom. It is a carboxylic acid with the simplest structure. Since it has no electron-withdrawing groups (EWG), it has the least stability for its conjugate base. Therefore, it is expected to be the weakest acid among the given compounds.
2. CH2ClCOOH (Chloroacetic acid): This compound contains a chlorine atom (EWG) attached to the carbonyl carbon. The presence of an electron-withdrawing group increases the stability of its conjugate base, making it more acidic than formic acid. Therefore, it is expected to be more acidic than HCOOH but less acidic than the next two compounds.
3. CHCl2COOH (Dichloroacetic acid): This compound contains two chlorine atoms (EWGs) attached to the carbonyl carbon. The presence of more EWGs further increases the stability of its conjugate base compared to chloroacetic acid, making it a stronger acid.
4. CH3COOH (Acetic acid): This compound is a simple carboxylic acid with a methyl group attached to the carbonyl carbon. It has no electron-withdrawing groups. Although it is a weaker acid compared to chloroacetic and dichloroacetic acid, it is expected to be more acidic than both formic acid and chloroacetic acid.
Therefore, the ranking from weakest to strongest acid is as follows:
1. HCOOH
2. CH2ClCOOH
3. CH3COOH
4. CHCl2COOH