Question

In the equilibrium $C{H}_{3}COOH+HF\rightleftharpoons C{H}_{3}COO{H}_2^{+}+F^{-}$ which one of the following statement is/are correct?

• A. $F^{-}$ is the conjugate acid of $C{H}_{3}COOH$
• B. $F^{-}$ is the conjugate base of $HF$
• C. $C{H}_{3}COOH$ is the conjugate acid of $C{H}_{3}COO{H}_2^{+}$
• D. $C{H}_{3}COO{H}_2^{+}$ is the conjugate base of $C{H}_{3}COOH$

Answer 1

The correct option is B $F^{-}$ is the conjugate base of $HF$

A conjugate acid is a species formed by gain of proton by the base.
Species formed by loss of proton from an acid is known as conjugate base.
The equilibrium reaction is
$C{H}_{3}COOH+HF\rightleftharpoons C{H}_{3}COO{H}_2^{+}+F^{-}$
in above reaction $F^{-}$ is formed by the loss of $H^{+}$ ion from $HF$ thus it is conjugate base of $HF$.