 a substance that changes color at a certain pH range.  HIn + H 2 O ↔ H 3 O + In - Acid color base color

 When just a small amount of indicator is added to a solution, the indicator does not affect the pH of the solution

 These are common indicators that can be seen around us. Many plants contain chemicals from the naturally colored:  Red cabbage  Lemon to be an acid-base indicator. Anthocyanin- is the pigment that causes the change of color in some natural indicators.

Identify its color: Methyl orange at high pH Methyl red at low pH Phenolphthalein at high pH Bromothymol blue at low pH

 they are used in soil testing kits to establish the approximate pH of soils. Soils are usually acidic in regions of high rainfall and heavy vegetation, and they are alkaline in more arid regions.  In swimming pools, chlorinating agents are most effective at a pH of about 7.4. At this pH the growth of algae is avoided, and the corrosion of pool plumbing is minimized. Phenol red is a common indicator used in testing swimming pool water.

 is a chemical reaction between an acid and a base that destroys the characteristic properties of both and produces salt and water.

H + (aq) + Cl - (aq) + Na + (aq) + OH - (aq) acid base → Na + (aq) + Cl - (aq) + H 2 O salt water

 Excess gastric in the stomach (acid indigestion) is typically neutralized by the ingestion of sodium bicarbonate (NaHCO 3 ) or neutralizing agent such as an antacid.

 due to behavior of cation and anion.

1. A salt of a strong acid and a strong base. Example: HCl (aq) + NaOH (aq) → NaCl (aq) + H 2 O (l) Strong acid strong base neutral

Example: HCl (aq) + NH 4 OH → NH 4 Cl (aq) + H 2 O (l) Strong acid weak base slightly acidic

Example: H 2 CO 3 (aq) + 2NaOH (aq) → Na 2 CO 3 + 2H 2 O Weak acid strong base slightly basic

Example: HCN (aq) + NH 4 OH → NH 4 CN (aq) + H 2 O Weak acid weak base  but it depends on acid dissociation and base dissociation constant.  if K b > K a, the solution will be basic, whereas if K b < K a, the solution will be acidic.

 For example, if the acid HClO has a K a of 3.4 x and the base NH 3 has a K b = 1.6 x 10 -5, then the aqueous solution of HClO and NH 3 will be basic because the K a of HClO is less than the K b of NH 3.

 Find the parent  Identify the conjugate acid and base Example: NaCl NH 4 Cl NH 4 CN

 2NaOH + H 2 SO 4 →  H 2 SO 4 + 2NH 4 OH →

Identify if it is acidic, basic or neutral using the two steps:  Na 2 CO 3  NaCl  Na 2 S

 Titration - the process of reacting a solution of unknown concentration with one of known concentration.  Volumetric analysis- the procedure of measuring the volumes of solutions  Titrant - a substance added slowly to a measured volume of an acid or a base solution of unknown concentration

 Neutralization point or equivalence point - the point at which the titrant is enough to fully neutralize the acid or base.

Aquarium Water Testing  Titration is used to test the underwater environment in fresh water and marine aquariums. Properties such as water pH and concentration of ammonia, nitrates and nitrites are measured and then corrected to ensure the survival of marine life being kept in the aquarium.