A stock solution of HNO3 is prepared and found to contain 13.1 M of HNO3. If 25.0 mL of the stock solution is diluted to a final volume of 0.500 L, the concentration of the diluted solution is M.

The diluted solution is 0.65 M

Explanation:

Dilution formula to solve the problem is:

M concentrated . V concentrated = M Diluted . V diluted

We can also make a rule of three though.

In 1000 mL of concentrated solution, we have 13.1 moles of  HNO₃

So in 25 mL we have (25 . 13.1 ) / 1000 = 0.327 moles of HNO₃

This moles are also in 0.500 L of diluted solution, the new molarity will be:

0.327 mol / 0.5L = 0.65 M

Molarity of diluted solution must be always lower than concentrated solution, otherwise the excersise is wrong.

If we replace in the formula

13.1 M . 25 mL = 500 mL . M diluted

M diluted = 13.1 m . 25 mL / 500 mL = 0.65 M

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.