Question

В трёх пробирках без этикеток содержатся растворы барий хлорида, натрий карбоната и натрий гидроксида. Использовав лишь один реагент, определите, в какой пробирке содержится каждое из этих веществ.

Answer 1

Я думаю, это H2SO4,
так как получается следующее:
BaCl2+H2SO4->BaSO4↓+HCl
Na2CO3+H2SO4->CO2↑+H2O+Na2SO4
NaOH+H2SO4->Na2SO4+H2O

Answer 2

Identification of Substances in Unlabeled Test Tubes

To determine which substance is present in each of the three unlabeled test tubes (containing barium chloride, sodium carbonate, and sodium hydroxide solutions), we can use a single reagent to perform a series of chemical reactions. By observing the reactions that occur, we can identify the substances in each test tube.

Procedure:

1. Add a few drops of hydrochloric acid (HCl) to each test tube, one at a time. 2. Observe the reactions that occur in each test tube. 3. Based on the reactions, identify the substances present in each test tube.

Interpretation of Results:

1. Test Tube 1: If a white precipitate forms when HCl is added, it indicates the presence of barium chloride (BaCl2). The reaction can be represented as follows:

BaCl2 + 2HCl → BaCl2·2H2O + 2HCl

The formation of a white precipitate confirms the presence of barium chloride in Test Tube 1.

2. Test Tube 2: If effervescence (bubbling) occurs when HCl is added, it indicates the presence of sodium carbonate (Na2CO3). The reaction can be represented as follows:

Na2CO3 + 2HCl → 2NaCl + H2O + CO2

The effervescence and the production of carbon dioxide gas confirm the presence of sodium carbonate in Test Tube 2.

3. Test Tube 3: If there is no significant reaction when HCl is added, it indicates the presence of sodium hydroxide (NaOH). Sodium hydroxide is a strong base and does not react with HCl. Therefore, no observable reaction occurs in Test Tube 3.

Based on these observations, we can conclude that: - Test Tube 1 contains barium chloride (BaCl2). - Test Tube 2 contains sodium carbonate (Na2CO3). - Test Tube 3 contains sodium hydroxide (NaOH).

Please note that the above conclusions are based on the provided information and the assumption that the substances in the test tubes are pure. It is always recommended to perform multiple tests and use additional confirmatory tests to ensure accurate identification of substances.

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