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CHEMISTRY HELP!
How to distinguish potassium hydroxide KOH and ammonia NH3? Give the observations, and chemical equations. Plz 更新: TRUE, I KNOW THE ALUMINIUM NITRATE METHOD LIKE 10 mins after i posted the question. LOL Just one more thing i want to know, NaOH also reacts with Copper (II) sulphate to form a blue precipitate, so does that mean KOH reacts with other metal ions like the way NaOH does?
最佳解答:
Chemical Method 1 : Add separately each of KOH solution and NH3 solution dropwise to aluminium nitrate solution until excess. KOH : A white precipitate is formed which is redissolved in excess KOH. Al(NO3)3(aq) + 3KOH(aq) → Al(OH)3(s) + 3KNO3(aq) and : Al(OH)3 + KOH(aq) → K[Al(OH)4](aq) or: Al^3+(aq) + 3OH^-(aq) → Al(OH)3(s) and: Al(OH)3(s) OH^-(aq) →[Al(OH)4]^-(aq) NH3 : A white precipitate is formed which is NOT redissolved in excess NH3. Al(NO3)3(aq) + 3NH3(aq) + 3H2O(l) → Al(OH)3(s) + 3NH4NO3(aq) or: Al^3+(aq) + 3OH^-(aq) → Al(OH)3(s) Chemical Method 2 : Add separately each of KOH solution and NH3 solution dropwise to copper(II) sulphate solution until excess. KOH : A blue precipitate is formed which is NOT redissolved in excess KOH. CuSO4(aq) + 2KOH(aq) → Cu(OH)2(s) + K2SO4(aq) or: Cu^2+(aq) + 2OH^-(aq) → Cu(OH)2(s) NH3 : A white precipitate is formed which is NOT redissolved in excess NH3. CuSO4(aq) + 2NH3(aq) + 2H2O(l) → Cu(OH)2(s) + (NH4)2SO4(aq) and: Cu(OH)2(s) + 4NH4(aq) → [Cu(NH3)4](OH)2(aq) or: Cu^2+(aq) + 2OH^-(aq) → Cu(OH)2(s) and: Cu(OH)2(s) + 4NH4(aq) → [Cu(NH3)4]^2+(aq) + 2OH^-(aq) Physical Method : Separately boil off the solvent of each solution. KOH : There is a left residue left. NH3 : There is NO residue left. 2010-03-06 23:16:37 補充： It is difficult to identify ammonia solution by smelling it if it is dilute. 2010-03-06 23:19:44 補充： Besides, smelling is usually not an acceptable method in identification of a compound and distinguishing between two compounds. 2010-03-13 00:43:08 補充： In the reaction with copper(II) nitrate solution, potassium hydroxide solution is used as a strong alkali. In such a reaction, potassium hydroxide solution and sodium hydroxide solution function identically. 2010-03-15 19:15:02 補充： Both KOH and NaOH can dissociate in water to give hydroxide ions, which react with copper(II) ions to give copper(II) hydroxide precipitate. Cu^2+(aq) + 2OH^-(aq) → Cu(OH)2(s)
其他解答:
You can distinguish them easily by your nose immediately . The KOH solution is odorless but the NH4OH solution has a pungent smell to wake you up . If you have a flu that you cannot smell very well then place a concentrated HCL solution near the solution , the one gives white smoke is NH4OH solution . You can distinguish them by simple observation not neccesary chemical equations !!!
CHEMISTRY HELP!
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發問:How to distinguish potassium hydroxide KOH and ammonia NH3? Give the observations, and chemical equations. Plz 更新: TRUE, I KNOW THE ALUMINIUM NITRATE METHOD LIKE 10 mins after i posted the question. LOL Just one more thing i want to know, NaOH also reacts with Copper (II) sulphate to form a blue precipitate, so does that mean KOH reacts with other metal ions like the way NaOH does?
最佳解答:
Chemical Method 1 : Add separately each of KOH solution and NH3 solution dropwise to aluminium nitrate solution until excess. KOH : A white precipitate is formed which is redissolved in excess KOH. Al(NO3)3(aq) + 3KOH(aq) → Al(OH)3(s) + 3KNO3(aq) and : Al(OH)3 + KOH(aq) → K[Al(OH)4](aq) or: Al^3+(aq) + 3OH^-(aq) → Al(OH)3(s) and: Al(OH)3(s) OH^-(aq) →[Al(OH)4]^-(aq) NH3 : A white precipitate is formed which is NOT redissolved in excess NH3. Al(NO3)3(aq) + 3NH3(aq) + 3H2O(l) → Al(OH)3(s) + 3NH4NO3(aq) or: Al^3+(aq) + 3OH^-(aq) → Al(OH)3(s) Chemical Method 2 : Add separately each of KOH solution and NH3 solution dropwise to copper(II) sulphate solution until excess. KOH : A blue precipitate is formed which is NOT redissolved in excess KOH. CuSO4(aq) + 2KOH(aq) → Cu(OH)2(s) + K2SO4(aq) or: Cu^2+(aq) + 2OH^-(aq) → Cu(OH)2(s) NH3 : A white precipitate is formed which is NOT redissolved in excess NH3. CuSO4(aq) + 2NH3(aq) + 2H2O(l) → Cu(OH)2(s) + (NH4)2SO4(aq) and: Cu(OH)2(s) + 4NH4(aq) → [Cu(NH3)4](OH)2(aq) or: Cu^2+(aq) + 2OH^-(aq) → Cu(OH)2(s) and: Cu(OH)2(s) + 4NH4(aq) → [Cu(NH3)4]^2+(aq) + 2OH^-(aq) Physical Method : Separately boil off the solvent of each solution. KOH : There is a left residue left. NH3 : There is NO residue left. 2010-03-06 23:16:37 補充： It is difficult to identify ammonia solution by smelling it if it is dilute. 2010-03-06 23:19:44 補充： Besides, smelling is usually not an acceptable method in identification of a compound and distinguishing between two compounds. 2010-03-13 00:43:08 補充： In the reaction with copper(II) nitrate solution, potassium hydroxide solution is used as a strong alkali. In such a reaction, potassium hydroxide solution and sodium hydroxide solution function identically. 2010-03-15 19:15:02 補充： Both KOH and NaOH can dissociate in water to give hydroxide ions, which react with copper(II) ions to give copper(II) hydroxide precipitate. Cu^2+(aq) + 2OH^-(aq) → Cu(OH)2(s)
其他解答:
You can distinguish them easily by your nose immediately . The KOH solution is odorless but the NH4OH solution has a pungent smell to wake you up . If you have a flu that you cannot smell very well then place a concentrated HCL solution near the solution , the one gives white smoke is NH4OH solution . You can distinguish them by simple observation not neccesary chemical equations !!!
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