[OhMyGod]

Hi guys,

Just want to ask whether KHSO4 can appear as a white ppt because I have this question whereby KI reacts with conc. H2S04 and yield pungent smelling gases and a dark brown solution containing a yellow ppt.

The equations are as follow, correct me if Im wrong.

KI + H2S04 --> HI + KHS04
2HI + H2S04 --> SO2(pungent gas) + I2 + 2H20
8HI + H2S04 --> H2S(pungent gas) + 4 I2 + 4H20
Dark brown soln is due to the reaction between I2(aq) + I-(aq) --> I3- (aq)

I presume KHS04 is a white solid and it appears yellowish in dark brown solution. Let me know if this is correct.

[Borek]

What yellow solids do you know?

[OhMyGod]

thx for the reply. from what i know. here are some ppt that are yellowish in colour.

AgI - yellow ppt.
CHI3 - yellow ppt.

But apparently, the answer my teacher suggested is something like its actually a White PPt and its appearance which is yellowish is due to its appearance in the red brown solution(I3-) .

So it goes back to my question to whether KHSO4 is actually the White PPt. that appears yellowish due to red brown soln?

[Borek]

KHSO₄ is most likely white - and I would not eliminate it as a potential product without further research. But what about elementar sulfur? It is cloudy white at first.

[macman104]

Couldn't you take a small amount of precipitate and test it for the presence of K⁺ and SO₄^2-?  I only know of flame testing for potassium, and for the sulfate ion, you can try and precipitate barium sulfate.  Seems like the easiest way to resolve the matter...

[Borek]

I doubt the experiment was really done, I suppose that's 'just' the question.

[macman104]

I doubt the experiment was really done, I suppose that's 'just' the question.

Ah, true, rereading, it does sound like that, sorry 'bout that.

[OhMyGod]

Thx for the reply. So i presume KHSO4 is indeed the white ppt which appear yellowish due to the reddish brown aqueous I3-