Question

Neutralization Reactions

In a clean, small container (glass vial or small paper cup), place about ten drops of an ammonia cleaner and two “squirts” of cabbage juice indicator.

Use a clean medicine dropper and count the number of drops of vinegar required to change the color of the solution from green to purple.

Repeat the above tasks with pickle juice or some solution that you found to have an acid pH slightly higher than vinegar.

Create a data table that summarizes your results of the two titrations.

Neutralization Reactions – comparison of two acid solutions neutralizing a base cabbage juice + ammonia solution

Drops of Ammonia	Vinegar	Pickle juice
10	6	8
10	7	7
10	6	8

In the titration of ammonia solution with vinegar, and with another acid solution with a slightly higher pH value, how did the amounts needed for the neutralization of the ammonia (signaled by the change from green to purple in the solution containing the ammonia and cabbage juice) compare? How does this comparison match the differences in pH values? What is the basis of any correlation between starting pH values of the two acids and amount required to neutralize the same amount of vinegar solution? Provide explanations for each for the three questions.

Answer 1

pH = -log[H^+] . So, greater the value of H^+ less will be the pH. So, if the acid has higher pH than that of vinegar, it means hydrogen ion concentration in the acid is less than hydrogen ion concentration in vinegar. So, the acid will require less amount of ammonia to completely neutralize it.

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Thus greater the amount of ammonia used less is the pH value.

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pH = -log[H+] . This means that concentration of H+ and PH are inversely proportional . Greater the hydrogen ion concentration less will be the pH and greater will be amount of ammonia required.