30.0 ml of 0.50 m naoh to neutralize 15.0 ml of hno3, what is the concentration (molarity) of the hno3?

First find the no. of moles of NaOH : 
30/1000 = 0.3 dm3 so no. of moles = 0.3*0.5 = 0.15 moles 

as NaOH reacts with HNO3 in a ratio of one to one, there must have been 0.15 moles of HNO3 too 
moles/volume = concentration 
volume= 15/1000 = 0.15 dm3 

concentration = 1.15/0.15 = 1 mol.dm-3 

The quicker way would be to realize that you used twice as much NaOH so the HNO3 had to be twice as strong

Idon't know hope someone you

Answer ozone (o3) is made of three atoms of oxygen, it is a molecule;