25cm3 Of 3g Of Hydrated Sodium Trioxocarbonate(iv) Solution (NaCO3XH2O)Per 250cm3 Was Neutralized By 13.20cm3 Of 0.16m Hydrochloric Acid Solution. Write The Equation For The Reaction. Calculate The Conc Of Base In Mol/dm3. Calculate The Molar Mass Of The Base. The Value Of X. The Percentage By Mass Of Water Of Crystallization.

Answer 1

Note that 0.16m means 0.16 MOLAL while 0.16 M means 0.16 MOLAR. I am sure you meant 0.16 M.
Na2CO3 + 2HCl == 2NaCl + H2O + CO2
mols HCl = M x L = approx 0.002 but you need a more accurate answer than that.
Using the coefficients, convert mols HCl to mols Na2CO3. That's 1/2 x 0.002 = approx 0.001 and that is in 25 cc so mol/dm^3 is approx 0.001/0.025 dm^ = about 0.004 M in the 25 cc. In the 250 cc initial solution that is 0.04 M. g Na2CO3 in the 250 cc solution is M x L = 0.04 x 0.25 x 106 = about 1.12g Na2CO3 in the 250 cc. So mass H2O must be about 3 - 1.1 = about 1.9 gH2O to 1.1 g Na2CO3. Convert that to the formula.
mols Na2CO3 = g/molar mass = about 1.12/106 = about 0.01
mols H2O = 1.9/18 = about .1
So the ratio is 1 Na2CO3 to 10 H2O which makes x in Na2CO3.xH2O = 10.