Q.)(i) How many moles of sulphur will be produced when 2 moles of H2S reacts with 11.2L of SO2at NTP?

2 Answers
Jul 8, 2017

I think you refer to the so-called "comproportionation reaction"....

Explanation:

The sulfide in "hydrogen sulfide" is OXIDIZED (i) to elemental sulfur, and the "sulfur dioxide" is REDUCED to elemental sulfur......(ii)

S^(2-) rarrS +2e^(-) (i)

SO_2 +4H^(+) + 4e^(-) rarrS+2H_2O (ii)

Both mass and charge are balanced in each reaction, as indeed they must be if we purport to represent chemical reality.....and so we simply add 2xx(i) + (ii) to eliminate the electrons to give........

2S^(2-) + SO_2 +4H^(+) + cancel(4e^(-)) rarr3S+2H_2O+cancel(4e^(-))

And we could simplify further to give.......

2H_2S + SO_2 rarr3S+2H_2O

And now (finally) we can address your question. "NTP" specifies a molar volume of 24.06*L*mol^-1......

With respect to SO_2 we have a molar quantity of (11.2*L)/(24.06*L*mol^-1)=0.466*mol..... And thus SO_2 is the limiting reagent and "hydrogen sulfide" is in excess.

And so we gets 3 xx an equivalent quantity of S, i.e. (3 * S)/(1 * SO_2) xx 0.466*molsxx32.06*g*mol^-1=44.8*g.

And even if you did this reaction carefully in a well-ventilated hood, it would still stink, and the upstairs chemists would come down to give you a beatdown......

Jul 8, 2017

0.188 mole S_8(s)

Explanation:

16H_2S(g) + 8SO_2(g) => 16H_2O(l) + 3S_8(s)
Since the form of sulfur is not specified, the above reaction is assumed.
*
**https://en.intl.chemicalaid.com/tools/equationbalancer.php?equation=H2S+%2B+SO2+%3D+S8+%2B+H2O

**Phases of H_2S & H_2O are assumed.

Given 2 moles H_2S + 11.2L SO_2(g) at STP
=> 2 "moles" H_2S + 0.50 mole SO_2(g) at STP
=> Limiting Reagent => 0.50 mole SO_2(g); 1 mole H_2S excess

8 moles SO_2(g) => 3 moles S_8(s)
0.50 mole SO_2(g) => ? moles S_8(s)

(8"mole"SO_2)/(0.50"mole"SO_2) = (3"mole"S_8(s))/(X)

X = ((0.50"mole"SO_2(g))(3"mole"S_8(s)))/(8"mole"SO_2(g)) = 0.188 "mole" S_8(s)