Science
28 Mar 09
28 Mar 09
Originally posted by najdorfslayerI don't know either. Want me to figure it out using Google?
1.
Does anyone know the equation for the 'test for nitrates'
Sodium nitrate + sodium hydroxide + aluminium > ?
P.S. I know the answer but I think it is difficult.
2.
What is formed when sodium reacts with nitric acid?
sodium + nirtic acid > ?
28 Mar 09
2 edits
Originally posted by dannyUchihaWell metals usually react with acids to produce salt + hydrogen
Hydrogen?
I think it goes like:
Na2 + 2HNO3 -> H2 + 2NaNO3
E.g. magnesium + hydrochloric acid > magnesium chloride + hydrogen.
However as nitric acid is an oxidising acid I was thinking maybe the N is reduced rather than the H!
28 Mar 09
Originally posted by najdorfslayerHow do you propose the reaction would occur?
Well metals usually react with acids to produce salt + hydrogen
E.g. magnesium + hydrochloric acid > magnesium chloride + hydrogen.
However as nitric acid is an oxidising acid I was thinking maybe the N is reduced rather than the H!
28 Mar 09
5 edits
Originally posted by dannyUchihaI know that nitric acid rarely produces hydrogen when it reacts with metals (excpet for magnesium and calcium,when cold and dilute)
How do you propose the reaction would occur?
In reality the products you obtain usually depends on the temperature and the concentration of the acid used.
A common reaction is copper with conc.nitric acid
Cu + 4HNO3 -> Cu(NO3)2 + 2NO2 + 2H2O
However I think this is only for metals low in the electrochemical series (e.g. Cu & Pb).
However becuase sodium is such a good reducing agent, maybe it will reduce the N further, here are the possible options. I would imagine you need to look at the standard reduction potentials.
1. Na + 2HNO3 -> NaNO3 + NO2 + H2O
(Here nitrate reduced from +5 to +4 in nitrogen dioxide)
2. 3Na + 4HNO3 -> 3NaNO3 + NO + 2H2O
(Here nitrate reduced from +5 to + 2 in nitrogen monoxide)
3. 8Na + 10HNO3 -> 8NaNO3 + 5H2O + N2O
(here nitrate reduced from +5 to +1 in dinitrogen oxide)
4. 6Na + 8HNO3 -> 6NaNO3 + 2H2O + NH3OHNO3
(Here the nitrate reduced from +5 to -1 in hydroxylammoniumn ions)
5. 8Na + 10HNO3 -> 8NaNO3 + NH4NO3 + 3H2O
(Here the nitrate reduced from +5 to -3 in ammonium ions)
Trust me you wont find this in any books or anywhere on the internet, that is why I asked the question!
It's all self worked out 😉
My gut feeling is number 5 😉