Chem (acid salt)

dilute sulphuric acid + dilute sodium hydroxide

H2S04+2NaOH-----> 2H20+ Na2SO4

the above one is the normal neutralization between dilute sulphuric acid + dilute sodium hydroxide

Where we need 2 mole of naoh to neutualize 1mole H2SO4

num of mole of naoh : num of mole of H2SO4= 2:1

so, it forms normal salt when there are enough NaOH for compelete
neutralization.

When the NaOH is the limiting factor
eg: 1mole dilute sodium hydroxide + 1mole dilute sulphuric acid

Mole ratio= 1;1

As the NaOH is limited ,the H2SO4 will just give out 1 H+ for one H2SO4 molecule
H2SO4--->HSO4- + H +

then
they can completely react with 1mole NaOH
NaOH+ HSO4- +H+----> NaHSO4 + H20


To conclude:
acid salt is formed when the alkali is limited
normal salt is formed when complete neutralization

2014-08-16 00:32:55 補充：
1)H2SO4 + NaOH--->NaHSO4 + H2O (acid salt)
2)H2SO4 + 2NaOh--->Na2SO4 + 2H2O (normal salt) ?ieEach H+ is replaced by Na+ step by step.when Na+ is ran out, the acid salt formed in step1 can't be 'further neutralized'. ''


yes~all the Na+ are used so the HSO4- stop dissociate
That's what i want to say

HSO4 is an acid salt, it will be ionize to form H+ and will eventually neutralize by OH- because NaOH is a strong acid even though it is dilute in concentration.

HSO4- => SO42- + H+

Therefore, SO42- will be the salt for the neutralization reaction


H2SO4 + 2NaOH--->Na2SO4 + 2H2O (normal salt)

Do you mean that the acid will 'detect' the number of moles and 'decide' what to form ?So when x mole H₂SO₄ reacts with x mole NaOH,NO Na2SO4 (normal salt) is formed ?

When x mole H₂SO₄ reacts with x mole NaOH, you get

A) H2SO4 + NaOH--->NaHSO4 + H2O (acid salt)

When x mole H₂SO₄ reacts with 2x mole NaOH, you get

B)H2SO4 + 2NaOh--->Na2SO4 + 2H2O (normal salt)

It depends on the mole ratio of H₂SO₄ and NaOH that you use.

2014-08-15 13:37:00 補充：
這樣想有點給予了 H₂SO₄ [智慧]。

H₂SO₄ 或 NaHSO₄ 會舆 NaOH 作用(化合) 直至可以反應的任何一個作用物 reactant 用盡為止。

例如用盡所有 NaOH 的同時，H₂SO₄ 亦剛好用完了，生成物 product 便會是 NaHSO₄。

而當全部 NaOH 用完時，H₂SO₄ 和 NaHSO₄ 亦由於反應而全部用完，生成物便會是 Na₂SO₄ 。

2014-08-16 15:03:50 補充：
A) H2SO4 + NaOH--->NaHSO4 + H2O (acid salt)

第一步 是 :

H₂SO₄(aq) → H⁺(aq) + HSO₄⁻(aq)

NaOH(aq) → Na⁺(aq) + OH⁻(aq)

反應的發生是由於 H⁺(aq) + OH⁻(aq) → H₂O(l)

伴隨而產生的 NaHSO₄(aq) 是以 Na⁺(aq) 和 HSO₄⁻(aq) 存在的。

2014-08-16 15:08:11 補充：
直至加熱使水蒸發才會得到 NaHSO₄(s)。

when Na+ is ran out, the acid salt formed in step1 can't be 'further neutralized'.

似乎應該是考慮是否所有 OH⁻(aq) 用完，而不是 Na⁺(aq)。