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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: chris on November 19, 2004, 10:54:22 PM

Title: balancing chemical equations
Post by: chris on November 19, 2004, 10:54:22 PM

 ???I need to know step by step on how to balance the equation As2+HNO3+H2O=H3AsO4+H2SO4+NO
Thanks

Title: Re:balancing chemical equations
Post by: kevins on November 20, 2004, 02:01:15 AM

please check the equation again?

because I can't find the Sulphur at the left hand side. ???

Title: Re:balancing chemical equations
Post by: ssssss on November 21, 2004, 02:17:59 AM

Quote from: kevins on November 20, 2004, 02:01:15 AM

please check the equation again?

because I can't find the Sulphur at the left hand side. ???

I think sulphur is supposed to be with Arsenic.

Title: Re:balancing chemical equations
Post by: AWK on November 22, 2004, 01:35:49 AM

As2S5+HNO3+H2O=H3AsO4+H2SO4+NO
15S(-2) =  S(+6) + 120e
40N(+5) + 120e = 40N(+2)
3As2S5 + 40HNO3  + 4H2O = 6H3ASO4 + 15H2SO4 + 40NO

As2S3+HNO3+H2O=H3AsO4+H2SO4+NO
6As(+3) + 9S(-2) = 6As(+5) + 9S(+6) + 84e
28N(+5) + 84e = 28N(+2)
3As2S3 + 28HNO3  + 4H2O = 6H3ASO4 + 9H2SO4 + 28NO

Note - reaction with HNO3 with evolving NO produce elemental S instead of H2SO4.
Yoy can oxidize S to H2SO4 using hot concentrated HNO3 and then NO2 is produced.