Question

250 ml 5 molar hno3 solution is mixed with 750 ml 25 molar hno3 solution.Find the molarity

Answer 1

Answer:

To prepare 250 mL of 2M HNO3:

Molarity = mass of solute /molar mass x volume of solution in litres

Mass of solute required =2 x 63 x 0.25

= 31.5 g

Volume of concentrated HNO3 required = 31.5 x 100 /70 = 45 mL

Mass of concentrated HNO3 required = 45 x density of concentrated HNO3

As density or specific gravity of concentrated HNO3 is not given, we can not proceed further.

Usually it is 1.42 g /mL, answer will be 45 x 1.42 = 63.9 g