Two weeks ago I posted a quiz about a reaction that I considered interesting. Its text is the following:
You have some chlorinated water. To the solution you add some sodium nitrate, but not in stoechiometrical amounts (the sodium nitrate is fewer than it is necessary to react entirely with the mixture). The reaction products shall be:
- Sodium hypochlorite and nitrogen dioxide
- Nitric acid, hydrochloric acid, hypochlorous acid, kitchen salt and sodium hypochlorite
- Sodium hypochlorite, hydrochloric acid and NO2
- Nitric acid, sodium hypochlorite, hydrochloric acid, kitchen salt and hypochlorous acid
- Kitchen salt, oxygen and hydrochloric acid
From the early beginning we can see that we have "chlorinated water". This means, that when we bubble chlorine into water the following reaction can be observed:
Cl2 + H2O → HClO + HCl
Next, we pour some NaNO3 into the solution. This means that the hypochlorous acid (HClO), and the hydrochloric acid will react to form nitric acid and sodium salts:
HClO + NaNO3 → NaClO + HNO3 HCl + NaNO3 → NaCl + HNO3
Because of the fact that the initial mixture is in excess, in the final solution will remain HClO and HCl too, but not even a drop of NaNO3.
To sum up the compounds of the final solution will be :
So the correct response is the fourth variant
I have seen that only 5 persons have answered to my quiz (from which only one of them has responded correctly), although I had expected a lot more to react. I know that this may be explained by the Christmas period that we are passing through, and people are more implied in celebrating this event in family than looking on chemistry blogs :-), and also by the fact that my blog is pretty new and hasn't got many followers yet. Merry Christmas and a Happy New Year!