Page 160 - Nilam_Publication_module_Chemistry_Form.pdf

MODULE • Chemistry Form 4

(b) Reaction with small amount until excess of ammonia solution:
Tindak balas dengan larutan ammonia sedikit demi sedikit sehingga berlebihan:

+
2+
Add a little Ca , K , Na + Add excess
aqueous
Solution solution of ammonia
contains: ammonia No precipitate Tambahkan Soluble
Larutan Tambah Tiada mendakan Cu (blue), larutan ammonia Larut Cu 2+
2+
sedikit larutan
mengandungi: ammonia Fe (green), berlebihan
2+
K , Na , Ca ,
+
+
2+
Fe (brown) 2+ 3+
3+
Mg , Al , Zn , Precipitate Insoluble Fe , Fe
2+
2+
3+
Pb , Fe , Fe , formed Coloured precipitate Add excess Tak larut
2+
2+
3+
Mendakan
Cu 2+ terbentuk Mendakan berwarna aqueous
ammonia Soluble
Tambahkan Larut Zn 2+
larutan ammonia
2+
3+
White precipitate Pb , Al , berlebihan
Mendakan putih Zn , Mg 2+
2+
2+
3+
Mg , Al ,
Insoluble Pb 3+
Tak larut
(c) Conclusion of the confirmatory test for colourless/white cations:
Kesimpulan ujian pengesahan bagi kation tanpa warna/putih:
2+ White precipitqte, soluble in excess of sodium hydroxide and ammonia solution
(i) Zn :
2+ White precipitate, insoluble in excess of sodium hydroxide and ammonia solution
(ii) Mg :
(iii) Al : White precipitate, soluble in excess of sodium hydroxide and insoluble in excess ammonia solution
3+
2+ White precipitate insoluble in excess of sodium hydroxide and no precipitate with ammonia solution
(iv) Ca :
+ No precipitate with sodium hydroxide solution and pungent smell released when heated
(v) NH :
4
(d) Conclusion of the confirmatory test for coloured cations.
Kesimpulan untuk ujian pengesahan bagi kation berwarna.
2+ Blue precipitate insoluble in excess of sodium hydroxide solution and soluble in excess ammonia solution
(i) Cu :
2+
(ii) Fe : Green precipitate, insoluble in excess of sodium hydroxide and ammonia solution
3+
(iii) Fe : Brown precipitate, insoluble in excess of sodium hydroxide and ammonia solution
(e) All cations can be identified with confirmatory test using sodium hydroxide solution and ammonia solution except
Al and Pb .
3+
2+
Semua kation boleh dikenal pasti dengan ujian pengesahan menggunakan larutan natrium hidroksida dan larutan ammonia kecuali
Al dan Pb .
2+
3+
(f) To differentiate between Al and Pb :
3+
2+
Untuk membezakan Al dengan Pb :
3+
2+
3+
–
–
2–
– Al and Pb are differentiated by double decomposition reaction. An aqueous solution containing SO / Cl / I
2+
4
2+
anion is used to detect the presence of Al and Pb .
3+
Al dan Pb boleh dibezakan dengan menggunakan tindak balas pernguraian ganda dua. Larutan akueus yang mengandungi
2+
3+
anion SO / Cl / I digunakan untuk mengesan kehadiran Al dan Pb .
3+
–
–
2+
2–
4
–
2–
–
2+
– Precipitate is formed when solution containing SO / Cl / I added to Pb .
4
Mendakan terbentuk apabila larutan mengandungi SO / Cl / I ditambah kepada Pb .
2+
2–
–
–
4
– No precipitate when solution containing SO / Cl / I added to Al .
2–
3+
–
–
4
Tiada mendakan terbentuk apabila larutan mengandungi SO / Cl / I ditambah keepada Al .
2–
3+
–
–
4
158
Nilam Publication Sdn. Bhd.
07-Chem F4 (3p).indd 158 12/9/2011 5:55:24 PM