hydrogen ion and hydroxide ion

1.
Acid properties are due to the presence of H3O^+(aq). However, H^+(aq) is usually used as the short form of H3O^+. There are two reasons :

Firstly, It is impossible to local an H3O^+ over a period of time. H3O^+ transfers an H^+ ion to its adjacent H2O molecule, and thus the H3O^+ becomes H2O while the adjacent H2O molecule becomes H3O^+. The transfer of H^+ proceeds continuously, and H3O^+ is actually the result of continuously transferring H^+ among H2O molecules. Therefore, H^+(aq) is a reasonable short form of H3O^+.

Secondly, in writing equation, it is complicated when writing H3O^+ instead of H^+.


2.
甘litmus paper change color都係depend on h30+而吾係h+ ?

Yes, but H^+ is a suitable short form of H3O^+.


3.其實base 都可2同acid有中和作用 ,即係alkali唔溶水都應該會同acid中和作用,點解仲要話 溶係水 出oh- 先有alkaline prop.?

A base is a compound that can neutralize acids. Basic properties means that it can neutralizes acids.

An alkali is a solution formed by dissolving a soluble base in water to give OH^- ions. Common alkaline properties include :
(1) It turns red litmus blue, and changes indicators to their acidic colours.
(2) Its pH is below 7.
(3) It is bitter in taste.
(4) It can neutralize acids.

Some bases are alkalis, but all alkalis are bases.


4.啲人成日話h+ 係 h30+ 甘 oh- 係吾係h302 -? why?

No.
The existence of H3O^+ is stated above.
OH^- ions exist in solution, but not H3O2^-.

2010-04-04 08:12:03 補充：
HCl gas does not react with Mg, because HCl does not contain H3O^+ (or H^+) ions.

2010-04-04 08:22:47 補充：
It is usually written as H^+(aq). H2O is included in (aq).

2010-04-06 23:28:40 補充：
H^+ 是 H3O^+ 的簡寫。
可以把 H3O^+ 看成一個 H^+ 附在一個 H2O molecule 上。
所以當用 H3O^+ 寫 equation 的時候，equation 的另一邊會多了一個 H2O。

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