Question

CHM130LL Lab 12 - Exploring Indicators Name: MEID Complete the following items by typing into the text box provided. The boxes will increase in size if additional space is necessary. Please be sure to save all your work as an MS Word document to submit properly. Part I - Calibration of Red Cabbage Juice Indicator A. Data Table 1: Calibration of Red Cabbage Juice Indicator with a Base Fill in the data table. Since your goal is to add sufficient ammonia to the red cabbage juice indicator to achieve a yellow color, you can stop data collection when you get a yellow solution. In other words, you may not need to use every line in the data table. However, you may need to add lines to the data table if 20 drops are insufficient to reach the yellow color. (8 pts) reperi Caraffinatellaria CHI LELLISTELLI

Answer 1

ANSWER - Question 1: Ammonia dissociation

The ammonia is a basic compound with the following chemical formula:

$NH_{3}$

The dissociation of ammonia in water produces ammonium ion (NH₄⁺ - conjugated acid) and hrydroxyl ion (OH^-):

$NH_{3}+H_{2}O\rightleftharpoons NH_{4}^{+}+OH^{-}$

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ANSWER - Question 2: Vinager dissociation

The vinegar is the name of acetic acid (an acid compound) with the following chemical formula:

$CH_{3}COOH$

The dissociation of acetic acid in water produces acetate ions (CH₃COO^- - conjugated base) and protons (H⁺):

$CH_{3}COOH+H_{2}O\rightleftharpoons CH_{3}COO^{-}+H_{3}O^{+}$

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ANSWER - Question 3: Chemical indicator

A chemical indicator is a substance/compounds that produces and visible sign when the conditions of reactions change. This visible sign could be a color change, a precipitate formation, bubbles formation, temperature change,among others.

Acid-base indicators are usually weak acids or bases that showed two different colors when they are in acid or basic solutions. The most common acid-base indicators are phenolphthalein, bromothymol blue and methyl orange.

How it works?

When a small amount of indicator is added to the solution of interest, the indicator (In) will be transformed into its acidic form (color 1 - HIn) or its conjugated form (basic form - color 2 - In^-)

$HIn+H_{2}O\rightleftharpoons In^{-}+H_{3}O^{+}$

• An acidic solution contains a high amount of H⁺, then the indicator will be in its acidic form HIn
• A basic solution contains a small amount of H⁺, then the indicator will be in its basic form In^-