Question

ДАЮ МАКСИМУМ БАЛЛОВ а)У пробірках знаходяться розчини: натрій карбонату, натрій силікату, натрій сульфату. До усіх розчинів додали розчин сульфатної кислоти. І побачили, що у пробірці Nel почав виділятися безбарвний газ без запаху, у пробірці Ne3 випав білий желеподібний осад, у пробірці Ne2 -- ніяких змін не спостерігали. Напишіть рівняння у молекулярному, повному і скороченому йонному вигляді відповідних реакцій і визначте, які солі знаходилися у пробірках Nel, 2, 3. 6). Запропонуйте, як експериментально розпізнати розчини нітратної кислоти і амоніаку з масовою часткою розчинених речовин 10% за фізичними хімічними властивостями

Answer 1

Ответ:

Лукоморье дуб зелений золотая цепь на дубе том и днём и ночью кот учёный все ходит по цепи кругом5-³

Answer 2

Identification of Substances in the Test Tubes

To identify the substances in the test tubes labeled Nel, Ne2, and Ne3, we can analyze the observations made after adding the sulfuric acid solution.

1. Test tube Nel: A colorless, odorless gas was observed to be released.

2. Test tube Ne3: No changes were observed.

3. Test tube Ne2: A white gelatinous precipitate formed.

Based on these observations, we can determine the substances present in each test tube.

- Test tube Nel: The colorless, odorless gas released indicates the presence of sodium carbonate (Na2CO3) in the test tube. The reaction can be represented by the following equation:

Na2CO3 + H2SO4 → Na2SO4 + H2O + CO2 [[1]]

- Test tube Ne3: No changes were observed, suggesting that there was no reaction. Therefore, the substance in this test tube is sodium sulfate (Na2SO4). The equation for the reaction would be:

Na2SO4 + H2SO4 → Na2SO4 + H2O [[1]]

- Test tube Ne2: The formation of a white gelatinous precipitate indicates the presence of sodium silicate (Na2SiO3) in the test tube. The reaction can be represented as:

Na2SiO3 + H2SO4 → Na2SO4 + H2O + SiO2 [[1]]

Experimental Identification of Nitric Acid and Ammonia Solutions

To experimentally distinguish between a nitric acid (HNO3) solution and an ammonia (NH3) solution with a mass fraction of dissolved substances of 10%, we can use their physical and chemical properties.

1. pH Test: Nitric acid is a strong acid and will have a low pH, typically below 3. Ammonia, on the other hand, is a weak base and will have a high pH, typically above 7. Therefore, performing a pH test using pH paper or a pH meter can help differentiate between the two solutions.

2. Smell Test: Ammonia has a distinct, pungent odor, while nitric acid does not have a strong smell. By carefully smelling the solutions, one can identify the presence of ammonia based on its characteristic odor.

3. Reaction with Indicators: Nitric acid is a strong oxidizing agent and can react with reducing agents, such as potassium iodide (KI), to liberate iodine (I2). This reaction can be observed by the appearance of a brown color. Ammonia, on the other hand, does not react with KI.

HNO3 + 3KI → HIO3 + 3KNO2 + I2 [[2]]

4. Solubility Test: Ammonia is highly soluble in water, while nitric acid is also soluble but to a lesser extent. Therefore, adding water to the solutions and observing the solubility can provide a clue about the nature of the solution.

By performing these tests, one can determine whether the solution contains nitric acid or ammonia based on their distinctive properties.

Note: It is important to exercise caution when handling chemicals and to follow proper safety protocols while conducting experiments.