salt and nuetralisation

1.
False.
If both the parent acid and alkali is strong the salt will be neutral.
e.g. NaCl (from NaOH and HCl), CaSO4 (from Ca(OH)2 and H2SO4)

If the parent acid is strong and the parent alkali is weak, the salt will be acidic (and vice versa)
e.g. NH4Cl (from NH3 and HCl)
NH4+ <--> NH3 + H+ (H+ formed accounts for its acidity)

e.g. Na2CO3 (from NaOH and H2CO3)
CO32− + H2O <--> HCO3− + OH− (OH- formed accoutns for its alkalinity)

2.
False.
Salts can be formed in various ways,
e.g. metal + acid --> metal salt + H2
metal + conc acid --> metal salt + gas (e.g. NO, NO2, SO2)
metal carbonate + acid --> metal salt + water + carbon dioxide
reactive metal + salt of less reactive metal --> less reactive metal + salt of reactive metal

therefore, both statements are false.

neutralization is a chemical reaction in which an acid and a base react to form a salt and water as the only products. (therefore, strictly speaking, reactions that give out CO2 is not neutralization. but, indeed, some books will consider carbonate + acid reactions are neutralization even though its not absolutely accurate.)

salt is the product formed from an acid in which the ionizable H atom(s) is/ are completely/ partly replaced by metal/ NH4+ ions.

A salt is a compound which is formed by replacing completely or partially the hydrogen in an acid by metal ion or ammonium ion.

For example, when the hydrogen in HCl is replaced by sodium ion, NaCl is formed which is a salt.

2012-06-21 12:10:27 補充：
Neutralization is the reaction between an acid and a base. However, confusion is made as there are several definitions of acids and bases.

2012-06-21 12:10:41 補充：
In F.4, bases are only defined as metal oxides and metal hydroxides, and alkalis as bases soluble in water. Under such definition :
acid + base → salt + water
acid + alkali → salt + water

2012-06-21 12:11:16 補充：
In higher forms, there are some other theories define what acids and bases are.

2012-06-21 12:12:14 補充：
For example, Bronsted-Lowry theory defines that an acid is an H^+ donor while a base is an H^+ acceptor, and neutralization is thus defined as the transfer of H^+ from an acid to a base.
2H^+(aq) + CO3^-(aq) → [H2CO3] → H2O + CO2
Refer to Bronsted-Lowry theory, the above reaction is neutralization.

Refer to CA's answer.

The equation in 2 should be Mg + 2HCl → MgCl2 + H2

1. All salts are neutral.
It is wrong, some salts will hydrolysis in aqueous solution. So, H+ / OH- ion will be produced

2. All salts are formed by neutralisation.
It is wrong.
eg. HCl + Mg -> MgCl + H2
MgCl is salt. but the reaction is not neutralisation.

Definition of neutralisation
acid + base -> salt + water
definition of acid(basic) : can release H+ ion
base: can release OH- ion or O2- (eg. MgO is base)

If produce CO2 , it is not neutralisation from my book.

2012-06-21 11:44:58 補充：
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. (from wiki)
I think cation and anion formed can be said a salt. May be all ionic compound? hope someone can clarify it.

2012-06-21 18:54:32 補充：
oh,, thanks andrew
MgCl2.
i made a big mistake