One liter of approximetely 0.25N HNO3 has been prepared. Upon titration it was found that 5.0 ml of the acid required 11.0 ml of 0.10N NaOH for neutrality. How much concetrated HNO3 at 15.8N must be added to one liter to make it exactly 0.25N?

Answer 1

So the first thing is to find the exact concentration of the acid.

concAcid*5=.10*.11
concacid=.22N

So in a liter, you have .22molesAcid
YOu need .25 moles
so you have to add .03 moles acid.

volumeacid=.03*15.8=.474
volume acid=molesacid/molarity=.03/15.8=.190e-3 liters or .190ml acid
check my thinking.