Question

Rank the following four acids in order of increasing bronsted acidity :
H2F+ , CH3OH, (CH3)2OH+ , CH3SH2+

Answer 1

Explanation:

Bronsted acids are the species which donate protons.

In the given species, we can see that fluorine is the most electronegative atom hence, $H_{2}F^{+}$ will not give proton easily. Therefore, its acidity will be the least.

Similarly, sulfur is also electronegative but less electronegative than fluorine atom. Hence, acidity of $CH_{3}SH_{2}^{+}$ is slightly more than $H_{2}F^{+}$.

Whereas $CH_{3}OH$ will have highest bronsted acidity and $(CH_{3})_{2}OH^{+}$ will be less acidic than $CH_{3}OH$.

Thus, we can conclude that order of increasing bronsted acidity is as follows.

      $H_{2}F^{+}$ < $CH_{3}SH_{2}^{+}$ < $(CH_{3})_{2}OH^{+}$ < $CH_{3}OH$