Question

what volume of a 25%(w/v) solution of HNO3 is needed to contain 12.6g HNO3?

Answer 1

25%(w/v) means, that 25 g of HNO3 contains in 100 ml of the solution, so the volume of a 25%(w/v) solution of HNO3 that is needed to contain 12,6 g HNO3 is: V = 12,6*100/25 = 50,4 ml