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Which negative ion does this test show I have?

I added silver nitrate and got a white precipitate, then added dilute nitric acid and the precipitate remained but I got effervescence. Thanks :smile:

Reply 1

The Warsmith

Should be chloride laddie

Posted from TSR Mobile

Reply 2

MsTyrell

Original post by Ser Alex Toyne

Should be chloride laddie

Posted from TSR Mobile

Why did I get effervescence?

Reply 3

Sideman420

Original post by MsTyrell

Why did I get effervescence?

Because the compound containing the chloride ion could also have other ions which produce effervescence with acid such as carbonate ions so CO2 is produced when reacted with nitric acid.

Reply 4

MsTyrell

Original post by Sideman420

Because the compound containing the chloride ion could also have other ions which produce effervescence with acid such as carbonate ions so CO2 is produced when reacted with nitric acid.

Okay, but if the compound contained no chloride at all the precipitate would dissolve when nitric acid was added wouldn't it?

Reply 5

Nucleotide

Original post by MsTyrell

Okay, but if the compound contained no chloride at all the precipitate would dissolve when nitric acid was added wouldn't it?

My inkling is this is a disproportionation reaction with cl2 and hno3 in which case NO2 gas would be formed hence your effervescence.

Double check that I'm not sure

Edit: misread your question so ignore this!

(edited 8 years ago)

Reply 6

Sideman420

Original post by MsTyrell

Okay, but if the compound contained no chloride at all the precipitate would dissolve when nitric acid was added wouldn't it?

If there were no chloride ions and we assume they were the only ions present, then the precipitate wouldn't form in the first place because silver chloride forms the precipitate.

Reply 7

scriberg

Original post by MsTyrell

Okay, but if the compound contained no chloride at all the precipitate would dissolve when nitric acid was added wouldn't it?

yep, the silver chloride compound will only dissolve in dilute ammonia

Reply 8

MsTyrell

Original post by Sideman420

If there were no chloride ions and we assume they were the only ions present, then the precipitate wouldn't form in the first place because silver chloride forms the precipitate.

But silver carbonate would also give a similar coloured precipitate?

Reply 9

Sideman420

Original post by MsTyrell

But silver carbonate would also give a similar coloured precipitate?

In that case yes, Ag2CO3 forms a false white precipitate. When you react this false white precipitate with nitric acid it dissolves since nitrates are always soluble and CO2 is produced giving effervescence so it can't be carbonate ions since the precipitate remained so I believe there must be chloride ions.

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Which negative ion does this test show I have?

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