Question

How to find the ph of a one litre solution containing 0.04 moles of koh and 0.02 moles of hno3?

Answer 1

KOH + HNO3 →KNO3 + H2O

This equation states that 1 mole of KOH reacts with 1 mole of HNO3 to produce 1 mole of KNO2KNO2 and 1 mole of H2OH2O.

0.04 moles of KOH will neutralize 0.04 moles of HNO3HNO3; however you only have 0.02 moles of HNO3HNO3.

In reverse, 0.02 moles of HNO3HNO3will neutralize 0.02 moles of KOH, leaving an excess of 0.02 moles of KOH per liter of solution.

[OH−OH−] = 0.02

pOH = -\log (0.02) = 1.7

pH + pOH = 14

pH = 14 – 1.7 = 12.3

pH = 12.3