Answer:
Concentration of
in sample is 0.25 M.
Step-by-step explanation:
From the reaction, one mole of
reacts with 3 moles of NaOH.
Now, number of moles of NaOH, n =


Therefore,
mol of NaOH reacts with
.
So, concentration of

Therefore, concentration of
in sample is 0.25 M.
Hence, this is the required solution.