Question

a beaker contains 500ml of 12m potassium nitrate .what is the molarity of the new solution if 250 ml more water is added

Answer 1

8.0 M.

Step-by-step explanation:

• It is known that the no. of millimoles after dilution is equal to the no. of millimoles before dilution.

∴ (MV) of KNO₃ before dilution = (MV) of KNO₃ before dilution.

• Before dilution:

M = 12.0 M, V = 500.0 mL.

• After dilution:

M = ??? M, V = 500.0 mL + 250.0 mL = 750.0 mL.

∴ M after dilution = (MV) before dilution / (V) after dilution = (12.0 M)(500.0 mL)/(750.0 mL) = 8.0 M.