Carbonic acid, H2CO3, has two acidic hydrogens. A solution containing an unknown concentration of carbonic acid is titrated with potassium hydroxide. It requires 20.0 mL of 3.840 M KOH solution to titrate both acidic protons in 50.2 mL of the carbonic acid solution.
1. Write a balanced net ionic equation for the neutralization reaction. Include physical states.
2. Calculate the molarity of the carbonic acid solution.

1) Net ionic equation :

2) 0.765 M is  the molarity of the carbonic acid solution.

Explanation:

1) In aqueous carbonic acid , carbonate ions and hydrogen ion is present.:

..[1]

In aqueous potassium hydroxide , potassium ions and hydroxide ion is present.:

..[2]

In aqueous potassium carbonate , potassium ions and carbonate ion is present.:

..[3]

From one:[1] ,[2] and [3]:

Cancelling common ions on both sides to get net ionic equation :

2)

To calculate the concentration of acid, we use the equation given by neutralization reaction:

where,

are the n-factor, molarity and volume of acid which is

are the n-factor, molarity and volume of base which is KOH.

We are given:

Putting values in above equation, we get:

0.765 M is  the molarity of the carbonic acid solution.

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation: