F.3 Chem 問題!! PLZZ

Putseparately a small amount of each of the six solutions into a test tube. Smell them carefully.
Dilute ammonia solution : It is the solution with a pungent smell.
Dilute ethanoic acid : It is the solution with a 'sour' smell.

Put separately about 2 cm³ of each of the rest four solutions in a test tube.To each test tube, add about 2 cm³ of dilute ammonia solution.
Dilute hydrochloric acid : It is in the test tube which feels warm.

Put separately about 2 cm³ of each of the rest three solutions in a test tube. To each test tube, add about 2 cm³ ofdilute hydrochloric acid.
Dilute sodium hydroxide solution : It is in the test tube which feels warm.

Put separately about 1/2 cm³ of each of the rest two solutions in a test tube. Heat each solution to dry.
Dilute sodium chloride solution : It is in the test tube with residue when thesolution is heated to dry.
Distilled water : It is in the test tube with residue when the solution is heated to dry.

You can use the nose to distinguish the dilute ammonia solution and dilute ethanoic solution because they produce different smell.


For the remaining solution(dilute NaOH, dilute HCl and dilute NaOH), mix two of the solution to ethanoic acid to see whether the temperature of the test tube is increased.

For dilute NaOH, energy is released when it is added to the ethanic acid.

For the other two solution, there is no chemical reaction and so, no observable result.


Burn the remaining two solutions to see which one is sodium chloride.

For dilute sodium chloride, white solid will appear when you burn it, whereas no solid appear when you burn the dilute HCl

2014-08-02 11:20:41 補充：
In order to distinguish which one is HCl and distilled water, add the solution to ammonia solution to see whther there is an increase in temperature.

HCl + NH3 => NH4Cl + H2O

There is no such reaction with water