At the midpoint of a titration curve . At the midpoint of a titration curve . The concentration of a conjugate base is twice that of the concentration of a conjugate acid The pH equals the pKa The ability of the solution to buffer is at its least effective The concentration of a conjugate base is 1/2 that of the concentration of a conjugate acid

The concentration of a conjugate base is twice that of the concentration of a conjugate acid

Explanation:

This is because at the midpoint, the number of moles of acid equals half the number of moles of base at the midpoint. This means that at the midpoint, half the analyte has been titrated.

Since the concentration of the conjugate acid is half that of the conjugate base at the midpoint, this implies that the concentration of the conjugate base is twice that of the conjugate acid.

Thus, at the midpoint of a titration curve the concentration of a conjugate base is twice that of the concentration of a conjugate acid

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.