Lab red cabbage juice

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Lab red cabbage juice

  1. 1. Name __________________________________________________________________________Date _______________________________ Group _________________________________ Lab Activity “ pH Indicator= Red Cabbage juice”Introduction:The nomenclature pH means “the potential of hydrogen” and refers to the ability of achemical to donate or accept hydrogen ions to other chemicals. Acids donatehydrogen ions while bases can accept them.In this lab, you will use the juice from red cabbage as a pH indicator to test commonhousehold liquids and determine their pH levels. Indicators are substances that readilychange their color due to changes in pH. You will mix cabbage juice with differenthousehold liquids and see a color change produced by a pigment called flavin (ananthocyanin) in red cabbage. Through this color change, you will be able tosuccessfully identify the approximate pH of common household liquids using the tablebelow:Method: 1. Pour 10 ml of red cabbage juice into a test tube 2. Pour 10 ml of the substance to its respective test tube and mix 3. Observe color change and record results in the Result Chart 4. Mix an acid with a base and observe changes. Record your results.Results:Chemical Color Change pH Acid or BaseDescribe you observations, results and conclusions:__________________________________________________________________________________________________________________________________________________________________________Questions:1.- What is an acid-base indicator?2.- What is the name of the pigment present in red cabbage?3.- Using your results, create a color-coded pH scale.4.- Besides litmus and red cabbage juice, mention 3 substances that can be used as anacid-base indicator.3.- What happens to the pH when a base is added to an acid?
  2. 2. 4.- Whenever you mix an acid with a base, they neutralize each other. Ifthis is the case, why is an antacid used to treat stomach aches?

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