In the reaction represented by the equation HF + H 2 O H 3 O+ + F- , a conjugate acid-base pair is: A. HF and H2O. B. F– and H3O+. C. H3O+ and H2O. D. HF and H3O+.

answer: option (a) is the correct answer.

explanation:

the measurement of hydrogen ions in a solution is known as ph.

if ph of a solution is less than 7 then the solution is acidic. if ph of a solution is greater than 7 then the solution is basic.

when the ph of a solution equals 7, then the solution is considered as neutral.

the ph of pure water is 7, therefore, it means that concentration of hydronium ions equals that of hydroxide ions.