Which anion is more acidic: TsO- or CN-?

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In summary, the conversation discusses the relative acidity of TsOH and HCN. The speaker explains that TsOH has a lower pKa value (-7) compared to HCN (pKa around 9). The conversation also mentions that the basicities of these acids are reversed when looking at their basic equivalents, with sodium cyanide being a stronger base than sodium tosylate. The speaker also mentions using these acids in substitution reactions and how their acidic strengths affect the leaving ability of their conjugate bases.
  • #1
maverick280857
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Which is more acidic: TsOH or HCN? (Ts is p-MeC6H4SO2-).
 
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  • #2
TsOH. TsOH has a pKa around -7, HCN is around 9.
 
  • #3
You may think from the reverse side; if you have the basic equivalents of these acids, the basicities are reversed. Let me give an example, sodium salts of these acids are bases, but sodium cyanide is a very strong base whereas sodium tosylate is not that strong.
 
  • #4
chem_tr said:
You may think from the reverse side; if you have the basic equivalents of these acids, the basicities are reversed. Let me give an example, sodium salts of these acids are bases, but sodium cyanide is a very strong base whereas sodium tosylate is not that strong.

:smile: Yeah I was working on this substitution reaction when this came along so I wanted to compare the leaving abilities of TsO- and CN- hence this problem. I did not know anything about their basic strengths. Instead we've been told to make acids from these anions (conjugate) and compare their acidic strengths. The stronger the acid, we weaker its conjugate base and correspondingly, the greater its leaving ability in a SN2 rxn.

Thanks and Cheers
Vivek
 

What is the acidity of TsOH and HCN?

The acidity of a substance refers to its ability to donate a proton (H+) in a chemical reaction. TsOH (tosylate acid) and HCN (hydrogen cyanide) are both considered strong acids, meaning they have a high tendency to donate a proton and thus have a low pH.

How do the acidity of TsOH and HCN compare?

In terms of acidity, TsOH is considered stronger than HCN. This is because TsOH has a more stable conjugate base, making it easier for the acid to donate a proton. Additionally, TsOH has a lower pKa (a measure of acid strength) compared to HCN.

What factors affect the acidity of TsOH and HCN?

The acidity of a substance can be affected by several factors, including the strength of the bond between the hydrogen and the atom it is attached to, the stability of the conjugate base, and the polarity of the molecule. In the case of TsOH and HCN, the strength of the bond and the stability of the conjugate base play a significant role in determining their acidity.

What are the common uses of TsOH and HCN?

TsOH is commonly used as a catalyst in organic reactions, specifically in esterification and etherification reactions. It is also used in the production of pharmaceuticals, dyes, and other chemicals. HCN is used in the production of plastics, synthetic fibers, and pesticides. It can also be found naturally in some plants and is used in certain industrial processes.

Are there any safety concerns when handling TsOH and HCN?

Both TsOH and HCN are toxic substances and should be handled with caution. TsOH can cause skin and eye irritation, while HCN is a highly poisonous gas that can be fatal if inhaled in large quantities. Proper safety precautions, such as wearing protective gear and working in a well-ventilated area, should always be taken when handling these substances.

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