Part B 1. (2 pts.) Write the reaction equation of ammonium ions with sodium hydroxide. How will the color of pH paper change if ammonium ions are present? 2. (2 pts.) Why do you need to convert Fe2 to Fe+3? Write the chemical equation for this conversion 3. (1 pts.) Appearance of what color will indicate the presence of iron(III)? Write the formula of an ion (not an equation of formation) that produces this color. 4. (2 pts.) 0.25M ammonium oxalate was added to unknown solution and a white precipitate was formed. What ion is present in the unknown solution? Support your answer with chemical equation. presence of zinc ions?
Solution
1. Reaction,
NH4+ + NaOH --> NH3 + H2O
NH4+ ions is acidic in nature and this the color of pH paper would be orange-red. When all of NH4+ has reacted with base NaOH, we would get greenish-blue color due to NH3.
2. Only Fe3+ reacts with SCN- to form complex Fe(SCN)2+ and thus, we must convert all of Fe2+ to Fe3+ prior to this reaction.
Fe2+ --> Fe3+ + e-
Fe3+ + SCN- <==> Fe(SCN)2+
3. Appearence of deep red color due to formation of Fe(SCN)2+ confirms presence of Fe3+ ions. The reactive ion here is SCN- species.
4. Ca2+ reacts with added oxalate C2O4^2- to form white precipitate of CaC2O4. Therefore, formation of white precipitate confirms Ca2+ is present.
Ca2+(aq) + (NH4)2C2O4(aq) --> CaC2O4(s) + 2NH4+(aq)
5. The presence of Zn2+ is confirmed by formation of grey-white precipitate of K2Zn[Fe(CN)6]2.
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Part B 1- (2 pts-) Write the reaction equation of ammonium ions with s.docx
1. Part B 1. (2 pts.) Write the reaction equation of ammonium ions with sodium hydroxide. How
will the color of pH paper change if ammonium ions are present? 2. (2 pts.) Why do you need to
convert Fe2 to Fe+3? Write the chemical equation for this conversion 3. (1 pts.) Appearance of
what color will indicate the presence of iron(III)? Write the formula of an ion (not an equation of
formation) that produces this color. 4. (2 pts.) 0.25M ammonium oxalate was added to unknown
solution and a white precipitate was formed. What ion is present in the unknown solution?
Support your answer with chemical equation. presence of zinc ions?
Solution
1. Reaction,
NH4+ + NaOH --> NH3 + H2O
NH4+ ions is acidic in nature and this the color of pH paper would be orange-red. When all of
NH4+ has reacted with base NaOH, we would get greenish-blue color due to NH3.
2. Only Fe3+ reacts with SCN- to form complex Fe(SCN)2+ and thus, we must convert all of
Fe2+ to Fe3+ prior to this reaction.
Fe2+ --> Fe3+ + e-
Fe3+ + SCN- <==> Fe(SCN)2+
3. Appearence of deep red color due to formation of Fe(SCN)2+ confirms presence of Fe3+ ions.
The reactive ion here is SCN- species.
4. Ca2+ reacts with added oxalate C2O4^2- to form white precipitate of CaC2O4. Therefore,
formation of white precipitate confirms Ca2+ is present.
Ca2+(aq) + (NH4)2C2O4(aq) --> CaC2O4(s) + 2NH4+(aq)
5. The presence of Zn2+ is confirmed by formation of grey-white precipitate of
K2Zn[Fe(CN)6]2.
![Part B 1. (2 pts.) Write the reaction equation of ammonium ions with sodium hydroxide. How
will the color of pH paper change if ammonium ions are present? 2. (2 pts.) Why do you need to
convert Fe2 to Fe+3? Write the chemical equation for this conversion 3. (1 pts.) Appearance of
what color will indicate the presence of iron(III)? Write the formula of an ion (not an equation of
formation) that produces this color. 4. (2 pts.) 0.25M ammonium oxalate was added to unknown
solution and a white precipitate was formed. What ion is present in the unknown solution?
Support your answer with chemical equation. presence of zinc ions?
Solution
1. Reaction,
NH4+ + NaOH --> NH3 + H2O
NH4+ ions is acidic in nature and this the color of pH paper would be orange-red. When all of
NH4+ has reacted with base NaOH, we would get greenish-blue color due to NH3.
2. Only Fe3+ reacts with SCN- to form complex Fe(SCN)2+ and thus, we must convert all of
Fe2+ to Fe3+ prior to this reaction.
Fe2+ --> Fe3+ + e-
Fe3+ + SCN- <==> Fe(SCN)2+
3. Appearence of deep red color due to formation of Fe(SCN)2+ confirms presence of Fe3+ ions.
The reactive ion here is SCN- species.
4. Ca2+ reacts with added oxalate C2O4^2- to form white precipitate of CaC2O4. Therefore,
formation of white precipitate confirms Ca2+ is present.
Ca2+(aq) + (NH4)2C2O4(aq) --> CaC2O4(s) + 2NH4+(aq)
5. The presence of Zn2+ is confirmed by formation of grey-white precipitate of
K2Zn[Fe(CN)6]2.](https://image.slidesharecdn.com/partb1-2pts-writethereactionequationofammoniumionswiths-230131004338-e4c34b72/85/Part-B-1-2-pts-Write-the-reaction-equation-of-ammonium-ions-with-s-docx-1-320.jpg)
