A 1.0 m aqueous solution of which substance would have the lowest ph?

a. nh3 strike reset

b. hcl strike reset

c. ba (oh) 2 strike reset

d. naf strike reset

Answer is: HCl (hydrochloric acid).

Hydrochloric acid is strong acid and in water dissociates:

HCl (aq) → H⁺ (aq) + Cl⁻ (aq).

Because acid gives a lot of hydrogen cations (H⁺), pH (pH = - log[H⁺]) is lower than seven (acidic solution).

Ammonia (NH₃) and barium hydroxide (Ba (OH) ₂) are base and their pH is higher that seven. Sodium fluoride (NaF) is neutral salt.