Question

How many ions are present if 2.0 moles of hno3 are completely dissolved in water?

Answer 1

Nitric acid(HNO3) is a strong acid so most of its component will dissociate into an ion form. When dissolved into water, nitric acid will have this reaction
HNO3= 1 H$^{+}$ + NO3$^{-}$ 

For every 1 mol of HNO3, there will be 1 mol of H+ ion and NO3- ion formed, which makes a total of 2 ions(degree of dissociation = 2). 
Then for 2 moles of HNO3 it would be: 2 moles * 2= 4 moles of ion

Answer 2

Answer: The number of ions that are present in nitric acid is $2.401\times 10^{24}$

Explanation:

We are given:

Moles of nitric acid = 2.0 moles

1 mole of nitric acid produces 1 mole of hydrogen ions and 1 mole of nitrate ions

Number of ions produced from nitric acid = 2 moles

According to mole concept:

1 mole of an ionic compound produces $6.022\times 10^{23}$ number of ions

So, 2.0 moles of nitric acid produces $(2.0\times 2\times 6.022\times 10^{23})=2.401\times 10^{24}$ number of ions

Hence, the number of ions that are present in nitric acid is $2.401\times 10^{24}$