[Shadow]

An electric spark is passed through a mixture made of H₂, O₂ and Cl₂ (volume is 44.8dm³ under standard conditions). After that, in the vessel were a liquid and a gass. To neutralize the liquid 3.2g of NaOH were spent. The gass that left in the vessel fully reacted with CuO (mass of the solid phase was reduced by 1.92g). Calculate the volumes of the gasses H₂, O₂ and Cl₂.
Is the liquid HCl, H₂O or HCl dilluted in H₂O?
CuO reacts with H₂?

[Borek]

Is the liquid HCl, H₂O or HCl dilluted in H₂O?

Water diluted in water? HCl was not liquid, it was gaseous. It was dissolved in the produced water after it condensed, but it didn't change the amount of HCl present.

CuO reacts with H₂?

Can you think of any other reaction that could lower mass of CuO?

[Shadow]

I didn't mean water dilluted in water.
I have HCl dissolved in H₂O. NaOH reacts with HCl so I can calculate the volume of Cl₂ at the beginning.
I thought of CuO+Cl₂ CuCl₂+1/2O₂  But it wouldn't lower the mass.
Why isn't CuO+H₂ okay?

[Shadow]

Any idea here?

[Borek]

Why isn't CuO+H₂ okay?

I never said it wasn't OK, I asked if you see other reaction that could consume H₂ - if not, that's the only reaction that could take place.

[Shadow]

H₂ reacts with O₂ to form water, then H₂ reacts with Cl₂ to form HCl which is dissolved in the water and it reacts with NaOH. At the end the remain H₂ reacts with CuO. Did I miss something now?

[Borek]

Looks OK to me.

[Arkcon]

Now, try writing out all the balanced chemical reactions.  You'll be able to see if you've missed anything, and you can begin to solve the problem for the volumes of reactants.

[Shadow]

Done, thanks very much .