Lin asked in 科學化學 · 1 decade ago

一個化學 有關ksp的觀念 0.0 好難懂 0.0

A solid mixture of calcium sulfate and calcium phosphate is added to a solution of hydrochloric acid. One of these dissolves and the other does not. Which one dissolves? Write an equation indicating this dissolution.

Calcium phosphate will dissolve. It is a salt of a weak acid and its aqueous solution is basic. When HCl is added, the following reaction takes place:

我還是不太董ㄟ 為什麼 這2種 calcium sulfate and calcium phosphate 只有其中一種會被 dissolves?

可以幫忙一下嘛 0.0

3 Answers

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  • 1 decade ago
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    1.

    硫酸鈣 ( CaSO4 ) 溶於水後呈中性。

    2.

    磷酸鈣 [ Ca3(PO4)2] 溶於水後呈弱鹼性,

    在酸性情況下有利其溶解。

    呈弱鹼性的原因是磷酸根會水解產生氫氧根:

    PO4(3-) + H2O --> HPO4(2-) + OH(-)

    3.

    鹽類在水中的酸鹼性,簡單來說,

    如果是強酸強鹼鹽則呈中性;

    如NaCl(強酸HCl+強鹼NaOH形成)。

    如果是弱酸強鹼鹽則呈鹼性;

    如CH3COONa(弱酸CH3COOH+強鹼NaOH形成)。

    如果是強酸弱鹼鹽則呈酸性;

    如NH4Cl(強酸HCl+弱鹼NH3形成)。

  • 1 decade ago

    感謝呢 0.0 原來如此 0.0

  • 1 decade ago

    calcium sulfate硫酸鈣,為正鹽,其不水解,呈中性。

    calcium phosphate磷酸鈣,為正鹽,水解後,呈鹼性(∵水解的關係)。

    所以加入HCl,只有磷酸鈣會因為酸鹼中和而溶解,硫酸鈣就不溶囉!

    Source(s): 自己
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