Three students each prepare a standard solution by dissolving 10.6g of solid from different bottles labelled 'sodium carbonate' in exactly 1dm3 of water. They use this standard solution in a titration to determine the exact concentration of a solution of sulphuric acid at approximately 0.1moldm−3. They each use a pipette to measure out exactly 25.00cm3 of the standard solution into a conical flask, they each use the same indicator and they each carry out their titrations with great care and accuracy.
The volumes of sulphuric acid solution that they each use are listed below. Only student A finds the correct concentration of the sulphuric acid. Student B is within 20% but student C is so far out that they know something is wrong. Student C asks for help and is reminded that some solids can contain water of crystallization. Student A uses anhydrous sodium carbonate, but what is 𝑥 in the formula Na2CO3⋅xH2O(s) for students B and C?
Student A: 23.75cm3
Student B: 20.20cm3
Student C: 8.80cm3
Calculate the exact concentration of the sulphuric acid. Give your answer to 3 significant figures.
help would be appreciated