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小 發表於 2015-12-27 11:43 PM (第 3014 天)
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1996 CE Chem Paper2(MC) 有條唔明,求教
Q17. A gardener bought a bag of potassium nitrate and a bag of ammonium sulphate to be used as fertilizers, He forgot to label the bags. Which of the following tests would enable him to distinguish between the two chemicals?
A. heating each chemical with dilute sulphuric acid
B. heating each chemical with sodium chloride solution
C. heating each chemical with potassium hydroxide solution
D. heating each chemical with acidified potassium dichromate solution
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答案係C,但我唔明
照計B呢,KNO3+NaCl就冇observable change,但(NH4)2SO4+NaCl應該出NH4Cl,即係有dense white fume,咁點解B係錯呢?
至於C呢,KNO3+KOH就冇observable change,jointus話KNO3+(NH4)2SO4會出NH4OH precipitate,但NH4OH咪即係NH3,係氣體黎? 我錯定jointus錯?
感謝各位!!!