F5 Chem 3questions(Acid)!URGEN

1)
H2SO4 + Na2SO3 → Na2SO4 + H2O + SO2
H2SO4 + Na2SO4 → no reaction

2)
H2SO4 + NaCl → NaHSO4 + HCl
(Na2­SO4 is formed only when the the reaction temperature is above 288°C. However, heat is not required in this reaction.)

3)
H2SO4 + NaNO3 → NaHSO4 + HNO3
(Na2­SO4 is formed only when the the reaction temperature is above 288°C. However, the reaction temperature is only about 100°C)

The reactions in the second and the third questions has been out of the HKCEE syllabus since 1995.

2010-02-18 22:21:37 補充：
In question 2), concentrated H2SO4 is used, and the HCl produced is gaseous.

In question 3), concentrated H2SO4 is used, and the HNO3 produced is gaseous.

化學反應是指有物質的改變，dilute acid：H2SO4(aq)
1)Na2SO3(s)+H2SO4(aq)--------Na2SO4(aq)+SO2(g)+H2O(l)
heat
Na2SO4(aq)+H2SO4(aq)----------Na2SO4(aq)+H2SO4(aq)
沒有反應

2)2NaCl(aq)+H2SO4(aq)----------------Na2SO4(aq)+2HCl(aq)
寫成離子形式
左邊:2Na+(aq)+2Cl-(aq)+2H+(aq)+SO42-(aq)
右邊:2Na +(aq)+SO42-(aq) +2H+(aq)+2Cl-(aq)
兩邊物質是一樣的，沒有任何反應

3)2NaNO3(aq)+H2SO4(aq)------------------Na2SO4(aq)+2HNO3(aq)
寫成離子形式
左邊:2Na+(aq)+2NO3-(aq)+2H+(aq)+SO42-(aq)
右邊:2Na+(aq)+SO42-(aq)+2H+(aq)+2NO3-(aq)
兩邊物質是一樣的，沒有任何反應

2010-02-18 22:30:53 補充：
使用稀酸:H2SO4(aq)便會冇反應

假如使用的是濃酸:H2SO4(l)
反應方程便會是回答者三的反應式

URGEN~URGEN~

1) H2SO4 + Na2(SO3)<=>H2SO3+Na2SO4
Further more, H2SO3(aq)<=>H2O(l)+SO2(g)

2) H2SO4 + 2NaCl <=> 2HCl+Na2SO4

3) H2SO4 + 2NaNO3 <=> 2HNO3+Na2SO4

2010-02-18 21:26:27 補充：
all are reversible reaction