Which of the following compounds would have the smallest value for pKa?

Question

Which of the following compounds would have the smallest value for pKa? (A) CHF2CH2CH2COOH (B) CH3CH2CF2COOH (C) CH2FCHFCH2COOH (D) CH3CF2CH2COOH

Tardigrade Admin · Accepted Answer

-F is a strong electron withdrawing group. Electron withdrawing group present nearer to the -COOH group has more acidic strength, hence low pKa value.

Q. Which of the following compounds would have the smallest value for $p K_{a}$ ?

$C H F_{2} C H_{2} C H_{2} COO H$

$C H_{3} C H_{2} C F_{2} COO H$

$C H_{2} FC H FC H_{2} COO H$

$C H_{3} C F_{2} C H_{2} COO H$

$- F$ is a strong electron withdrawing group. Electron withdrawing group present nearer to the $- COO H$ group has more acidic strength, hence low $p K_{a}$ value.

Q. Which of the following compounds would have the smallest value for pKa​?

CHF2​CH2​CH2​COOH

CH3​CH2​CF2​COOH

CH2​FCHFCH2​COOH

CH3​CF2​CH2​COOH