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AQA A-Level chemistry group 7

Hey guys,
quick question about group 7, particularly sodium iodide and concentrated sulphuric acid
for the equation that produces H2S, does the HI react with H2SO4
ie 8HI + H2SO4 ---> 4I2 + H2S + 4H2O

or does the HI react with SO2
6HI + SO2 ---> H2S + 3I2 +2H2O

im really confused about this, so any help would be appreciated. what have u guys seen more often in mark schemes, and would the wording of the question be different?

sorry, another quick q
question:
Sodium bromide reacts with concentrated sulfuric acid in a different way from sodium chloride.
Write an equation for this reaction of sodium bromide and explain why bromide ions react differently from chloride ions.

mark scheme:
2NaBr + 2H2SO4 ----> Na2SO4 + Br2 + SO2 + 2H2O
Allow ionic equation
2Br– + 2H2SO4 Br2 + SO42– + SO2 + 2H2O

is this ionic equation the same as H2SO4 + 2HBR ---> Br2 + SO2 +2H2O once its been cancelled down?

thanks so much x
(edited 1 year ago)
Original post by quirkycat123
Hey guys,
quick question about group 7, particularly sodium iodide and concentrated sulphuric acid
for the equation that produces H2S, does the HI react with H2SO4
ie 8HI + H2SO4 ---> 4I2 + H2S + 4H2O

or does the HI react with SO2
6HI + SO2 ---> H2S + 3I2 +2H2O

im really confused about this, so any help would be appreciated. what have u guys seen more often in mark schemes, and would the wording of the question be different?

sorry, another quick q
question:
Sodium bromide reacts with concentrated sulfuric acid in a different way from sodium chloride.
Write an equation for this reaction of sodium bromide and explain why bromide ions react differently from chloride ions.

mark scheme:
2NaBr + 2H2SO4 ----> Na2SO4 + Br2 + SO2 + 2H2O
Allow ionic equation
2Br– + 2H2SO4 Br2 + SO42– + SO2 + 2H2O

is this ionic equation the same as H2SO4 + 2HBR ---> Br2 + SO2 +2H2O once its been cancelled down?

thanks so much x

Hi there.

I personally learnt the first equation for the HI reaction to produce hydrogen sulfide.

And I think the cancelled down versions would be the same too.

@5hyl33n could correct/confirm this :smile:

Hope this somewhat helps though! :smile:
Original post by TriplexA
Hi there.

I personally learnt the first equation for the HI reaction to produce hydrogen sulfide.

And I think the cancelled down versions would be the same too.

@5hyl33n could correct/confirm this :smile:

Hope this somewhat helps though! :smile:

thank you so much, this is really appreciated! :smile:

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