Question

Опыт 3. Взаимодействие уксусной кислоты с основаниями. Посмотрите видео-опыт «Взаимодействие уксусной кислоты с основаниями» В пробирку налейте 1 мл гидроксида натрия и добавьте 1 каплю фенолфталеина. • Что наблюдаете? Почему? Затем добавьте к содержимому пробирки уксусную кислоту. • Почему происходит обесцвечивание? Запишите уравнения химических реакций, назовите продукты.

Answer 1

В начале в пробирке есть гидрооксид натрия (NaOH), который имеет щелочную среду, за счет ОН(-). Фенолфталеин-индикатор, который реагирует на присутствие Н(+)кислой среды или ОН(-) щелочной, а так же нейтральной. В щелочной среде раствор фенолфталеина окрашивается в розовый цвет. При добавлении уксусной кислоты, раствор обесцвечивается, так как идет реакция нейтрализации и среда становится нейтральной.
СН3СООН+NaOH=CH3COONa+H2O

Answer 2

Interaction of Acetic Acid with Bases

When acetic acid interacts with bases, several chemical reactions take place, resulting in observable changes. Let's go through the steps of the experiment and discuss the observations and the underlying chemical reactions.

1. Observation after Adding Sodium Hydroxide and Phenolphthalein - When 1 ml of sodium hydroxide is added to the test tube and 1 drop of phenolphthalein is included, the solution turns pink or magenta. - This color change occurs because phenolphthalein is a pH indicator that changes color in response to the acidity or basicity of a solution. In the presence of a base like sodium hydroxide, phenolphthalein turns pink.

[[Source 1]] - . 1 1 . ...

2. Observation after Adding Acetic Acid - Upon adding acetic acid to the contents of the test tube, the pink color disappears, and the solution becomes colorless. - This decolorization happens because acetic acid neutralizes the base (sodium hydroxide) present in the solution, leading to a decrease in pH and causing the phenolphthalein to lose its pink color.

[[Source 2]] - . 3 . + 1 + 1 + 1-2 .

3. Chemical Reactions and Products - The chemical reaction between acetic acid (CH3COOH) and sodium hydroxide (NaOH) can be represented by the following equation: ``` CH3COOH + NaOH → CH3COONa + H2O ``` The reaction produces sodium acetate (CH3COONa) and water (H2O).

[[Source 3]] - . ... 2-3 20 ...

- The overall reaction can be summarized as the neutralization of acetic acid by sodium hydroxide, resulting in the formation of a salt (sodium acetate) and water.

4. Conclusion - The experiment demonstrates the neutralization reaction between acetic acid and sodium hydroxide, leading to the formation of a salt and water, along with the observable color changes due to the pH indicator, phenolphthalein.

[[Source 4]] - 9 '... , . : 1. 2 . ? ...

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