1) <span>NaNO3 and H2O - no reaction , it is dissolution
2) no hydrogen to make water
3) </span><span>Fe(OH)3 (base) and H2SO4(acid))
base +acid ----> salt +water
4) </span><span>Li2O and Ba(OH)2
basic oxide and base ----> no reaction
so Answer number 3)
</span> 2Fe(OH)3 +3 H2SO4 ------> Fe2(SO4)3 + 6H2O<span>
</span>
The transitions which fall to the lowest principle position release the greatest energies. In this case, this would be the transition from the 5p to the 3s orbital (a Paschen transition).
Hope this helps!