Determining pH’s of Various Household Products Using a Natural IndicatorBy: Paige GarciaMrs. La Salle Chemistry Period 3

Purpose• To determine the pH of various household

products by using a natural indicator using a homemade pH scale.

Materials • Red Cabbage • Knife• Cutting Board• ½ cup (measuring)• Hot water • 2 Jars• White Towel• 1 Teaspoon• Tape• 3 Sheets of Paper• Pencil

• Ruler• 7 Clear Cups• Dropper• White Vinegar• Baking Soda• Ammonia • Windex • Laundry

Detergent • Soft Soap ‘Sea

Minerals” Hand Soap

• Simply Limeade

Procedure• 1. Finely chop the red cabbage and put ½ cup of the chopped cabbage

into a jar, add ½ cup of hot water to the jar of cabbage. Stir and crush the chopped cabbage until the water is distinctly colored.

• 2. Strain the extract through a towel into a clean jar.• 3. Tape three sheets of paper together end to end and draw a line along

the center and label at 5cm intervals from numbers 1-14 and use it as the pH scale.

• 4. Pour the natural indicator to about 1cm depth in 7 clear containers. Add several drops of white vinegar to the first container of indicator and determine the pH (3). Add a pinch of baking soda to the second container and determine the pH (11). Add several drops of ammonia to the third container of indicator and determine the pH (9). Add several drops of Windex to the fourth container of indicator and determine the pH (8). Add several drops of laundry detergent to the fifth indicator and determine the pH (11). Add several drops of soft soap’s ‘Sea Minerals’ to the sixth container of indicator and determine the pH (6). Add several drops of Simply Limeade to the seventh container of indicator and determine the pH (1)

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Data• White Vinegar – pH 3 (Acid)• Ammonia – pH 9 (Base)• Baking Soda – pH 11 (Strong Base)• Windex – pH 8 (Weak Base)• Laundry Detergent – pH 11 (Strong Base)• Soft Soap ‘Sea Minerals’ Hand Soap – pH 6 (Weak

Acid)• Simply Limeade Juice – pH 1 (Strong Acid)

Conclusion/Analysis Part One• Acids are hydrogen containing compounds that ionize to yield

hydrogen ions in aqueous solutions (according to Arrhenius), hydrogen-ion donor (Brnsted–Lowry), accepts a pair of electrons during a reaction (Lewis). Acids taste sour, change color of an acid-base indicator, electrolytes in an aqueous solution. Bases are compounds that ionize to yield hydroxide ions in an aqueous solution (according to Arrhenius), a hydrogen-ion acceptor (Brnsted–Lowry), donates a pair of electrons. Bases taste bitter, feel slippery, change the color of an acid-base indicator, electrolytes in an aqueous solution. On the pH scale an acid is between 1 and 6, neutral solutions have a pH of 7 and bases have a pH between 8 and 14. Knowing the pH’s of substances is important in medicine, agriculture, nutrition, even water treatments to determine whether substances are harmful or not, without purified water at a pH close to 7 humankind could face many hardships. Cleaning products most commonly tend to be basic because there high concentration of hydroxide ions be when a surface requires cleaning, the selection and use of the proper cleaning product results in the surface being cleaned or neutralized.

Conclusion/Analysis Part Two• 1. During acidic conditions the indicator is a redish pink color,

while under neutral conditions the indicator remained a stable purple. Under basic conditions the indicator became a darker purple and blue.

• 2. A change in pH shows the elimination of H+ ions in the case of acids or OH- ions in the case of bases. The change in concentrations of H+ ions and OH- ions are chemical changes are responsible for the color change.

• 3. White Vinegar (Acidic), Ammonia (Basic), Baking Soda (Basic), Windex (Basic), Laundry Detergent (Basic)

• Soft Soap ‘Sea Minerals’ Hand Soap (Acidic), Simply Limeade Juice (Acidic)

• 4. Most of the cleaning products I tested were part of the basic group on the pH scale.