2Na + H₂ = 2NaH (sodium-hydride).
Answer:
5 1 2 4and 3 this is correct way
If the difference in electronegativtiy for the atoms in a bond are greater than 0.4,we consider the bond polar, if the electronegativity is less than 0.4, we consider it non polar. if there are no polar bonds, the molecule is non polar.
It has a 1:2 ratio
If you look at the start of PbO2 it does not have a number so that is the one and if you look at 2H2O that has a 2 in front so that is where you get the 1:2 ratio