Khimiia 10 Klass Rudzitis 2 Prakticheskaia Rabota • Trusted

Carboxylic acids can be identified by their acidity or their reaction with carbonates. Add a drop of litmus or a small amount of Na2CO3cap N a sub 2 cap C cap O sub 3 to the sample. Observation: Litmus turns red; Na2CO3cap N a sub 2 cap C cap O sub 3 produces effervescence (bubbles of CO2cap C cap O sub 2 Equation:

CH3CHO+2Cu(OH)2ΔCH3COOH+Cu2O↓+2H2Ocap C cap H sub 3 cap C cap H cap O plus 2 cap C u open paren cap O cap H close paren sub 2 cap C cap H sub 3 cap C cap O cap O cap H plus cap C u sub 2 cap O down arrow positive 2 cap H sub 2 cap O 4. Summary Table of Results Na2CO3cap N a sub 2 cap C cap O sub 3 Gas evolution ( CO2cap C cap O sub 2 Glycerol Bright blue solution Aldehyde / Glucose Brick-red precipitate 5. Final Conclusion khimiia 10 klass rudzitis 2 prakticheskaia rabota

Polyhydric alcohols react with copper(II) hydroxide at room temperature. Add freshly prepared to the test tube. Carboxylic acids can be identified by their acidity

The primary goal of this experiment is to use qualitative chemical reactions to identify unknown organic substances in test tubes, such as . 2. Prepare Reagents and Equipment Summary Table of Results Na2CO3cap N a sub

To perform the identification, the following reagents are required: Freshly prepared (copper(II) hydroxide), formed by mixing NaOHcap N a cap O cap H CuSO4cap C u cap S cap O sub 4 Blue litmus paper or universal indicator. Na2CO3cap N a sub 2 cap C cap O sub 3 (sodium carbonate) or NaHCO3cap N a cap H cap C cap O sub 3 (sodium bicarbonate). Test tubes, a spirit lamp, and a test tube holder. 3. Execution of Qualitative Tests Step A: Identifying Carboxylic Acids (e.g., Acetic Acid)

2CH3COOH+Na2CO3→2CH3COONa+H2O+CO2↑2 cap C cap H sub 3 cap C cap O cap O cap H plus cap N a sub 2 cap C cap O sub 3 right arrow 2 cap C cap H sub 3 cap C cap O cap O cap N a plus cap H sub 2 cap O plus cap C cap O sub 2 up arrow Step B: Identifying Polyhydric Alcohols (e.g., Glycerol)

Both aldehydes and glucose (which contains an aldehyde group) react with upon heating. Add and heat the mixture gently.