This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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Here are the answers to the questions: 8) Write short note on caustic soda test The caustic soda test, also known as the sodium hydroxide test, is a qualitative analysis method used to identify certain metal cations in a solution. When sodium hydroxide (NaOH) solution is added to a solution containing metal ions, a precipitate of the metal hydroxide is often formed. The characteristic color of the precipitate and its solubility in excess NaOH can help in the identification of the specific metal cation. For example, Fe^2+ forms a dirty green precipitate, while Cu^2+ forms a blue precipitate. 9) Though the preliminary tests are exploratory in nature and rarely conclusive yet they provide information about various acid and basic radicals. Briefly discourse this statement with respect to physical appearance test only. Preliminary tests, such as observing the physical appearance of a salt, are indeed exploratory and not conclusive on their own. However, they provide valuable initial clues about the possible presence of certain acid and basic radicals. For instance, the color of a salt can indicate the presence of specific transition metal cations (e.g., blue suggests Cu^2+, green suggests Ni^2+ or Fe^2+, yellow/brown suggests Fe^3+). The physical state (solid, liquid), crystal shape, and texture can also narrow down the possibilities, guiding the selection of more specific confirmatory tests. 10) A salt mixture containing Na_2CO_3 and NaSO_3 is to be treated with dilute H_2SO_4. Briefly explain how you can identify the acid radicals present in the mixture. To identify the acid radicals (CO_3^2- and SO_3^2-) in the mixture: Step 1: Add dilute sulfuric acid (H_2SO_4) to the salt mixture. Both carbonate and sulfite will react to produce gases. Na_2CO_3(s) + H_2SO_4(aq) → Na_2SO_4(aq) + H_2O(l) + CO_2(g) Na_2SO_3(s) + H_2SO_4(aq) → Na_2SO_4(aq) + H_2O(l) + SO_2(g) Step 2: Pass the evolved gases through an acidified potassium dichromate(VI) solution (K_2Cr_2O_7/H_2SO_4). Sulfur dioxide (SO_2) will reduce the orange dichromate solution to a green chromium(III) solution. This confirms the presence of the sulfite radical (SO_3^2-). Carbon dioxide (CO_2) does not react with acidified dichromate. Step 3: After passing through the acidified potassium dichromate(VI) solution (which removes SO_2), pass the remaining gas through limewater (Ca(OH)_2). If the limewater turns milky, it indicates the presence of carbon dioxide (CO_2), confirming the carbonate radical (CO_3^2-). This sequence ensures that the test for CO_2 is not interfered with by SO_2, as SO_2 also turns limewater milky. Send me the next one 📸