[khwcm]

what is the use of dipping pt wire to Conc. HCl b4 perform flame test?
i heard that Conc HCl can "clear" the Pt wire, but how is it works?
doesnt chlorine will "attack" pt wire?
and why conc nitric acid or H2SO4 was not choosen?

[AWK]

Metals chlorides are most volatile salts. HCl does not reacts with Pt.

[khwcm]

so how is HCl "clean" the wire?

[Pradeep]

Pt is a good adsorbant. I think it cleans HCl by adsorbing heavy metal ions.

[Schrödinger]

Quote from OP :

what is the use of dipping pt wire to Conc. HCl b4 perform flame test?
i heard that Conc HCl can "clear" the Pt wire, but how is it works?

Pt is a good adsorbant. I think it cleans HCl by adsorbing heavy metal ions.

I think the OP wanted to know how HCl cleans Pt, not the reverse.

Please do not misunderstand my tone 

[OrganicSynthesis]

Maybe the acid just reacts with the outer impurities of the Pt (e.g. Aluminum).

[AWK]

Maybe the acid just reacts with the outer impurities of the Pt (e.g. Aluminum).

Yes, you are right. Some impurities are soluble in concentrated HCl used for washing; others are converted into chlorides on the surface of wire - chlorides are the most volatile salts among common salts; then are removed from wire by heating.

[khwcm]

how about:
there might be organic impurities in the salt, where the organic impurities will form volatile chloride with conc HCl instead of forming metal chloride?

[Schrödinger]

how about:
there might be organic impurities in the salt, where the organic impurities will form volatile chloride with conc HCl instead of forming metal chloride?

Organic halides do have low boiling points and hence the volatility at room temperature, but they will be formed only if a reaction between HCl and he organic impurity is possible.


quote from AWK :
Metals chlorides are most volatile salts. HCl does not reacts with Pt.

quote from AWK:
Some impurities are soluble in concentrated HCl used for washing; others are converted into chlorides on the surface of wire - chlorides are the most volatile salts among common salts; then are removed from wire by heating.



I too would prefer to think of inorganic impurities on a Pt wire than organic ones. Please feel free to correct me if I am wrong.