Respuesta :

An acid is a compound that produces hydrogen ions when dissolved in water. The pH of acid is less than 7 because it is rich in H+ concentration. Basic solutions have pH greater than 7 because it is rich in OH-. Neutral solutions meanwhile have pH equal to 7.

Answer: a. acid

Explanation:

a. Acids are those substances which either donates hydrogen ions [tex](H^+)[/tex] when dissolved in water or accepts a pair of electrons.

[tex]HCl\rightarrow H^++Cl^-[/tex]

b. Buffer is a solution which resist changes in pH on addition of small amounts of acid or base into it.

c. Bases are those substances which either donates hydroxide ions [tex](OH^-)[/tex] when dissolved in water or donates a pair of electrons.

[tex]NaOH\rightarrow Na^++OH^-[/tex]

d. Indicators are chemical compounds which show a change or appearance in color at particular pH. Example: litmus