An unknown weak acid, ha, it titrated with 1.2 m naoh. the ph at the halfway point of this titration was found to be 4.102. if the initial ph of the weak acid solution (before titration) has a ph of 2.308, what was the concentration of the weak acid solution?

0.311 M

Explanation:

HA, our weak acid, reacts with NaOH by the following equation given below:

This may also be represented by the net ionic equation for this acid-base reaction:

During the titration up to the equivalence point, we would have some HA remaining and some produced. That said, we have a weak acid and its conjugate base forming a buffer. We may apply the Henderson-Hasselbach equation for buffers here:

At midpoint, half of HA reacts to produce half of , meaning when half of equivalence volume of NaOH is added.

This implies that:

at midpoint. We may then find the acid ionization constant for this acid:

The initial molarity has to be found now. We know that the initial pH is:

Since , then

Using an ICE table, for some initial molarity of acid, , we may write the equilibrium constant expression as:

Solve for the initial molarity of HA:

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.