How many moles of HNO3 are present if 4.90*10-2 mol of Ba (OH) 2 was needed to neutralize the acid solution?

0.098 moles

Explanation:

Let y represent the number of moles present

1 mole of Ba (OH) ₂ contains 2 moles of OH - ions.

Hence, 0.049 moles of Ba (OH) 2 contains y moles of OH - ions.

To get the y moles, we then do cross multiplication

1 mole * y mole = 2 moles * 0.049 mole

y mole = 2 * 0.049 / 1

y mole = 0.098 moles of OH - ions.

1 mole of OH - can neutralize 1 mole of H+

Therefore, 0.098 moles of HNO₃ are present.