A 4.00 cm3 sample of a concentrated solution of phosphoric acid, H3PO4\text{H}_3\text{PO}_4H3PO4, was carefully diluted with distilled water. More water was then added until the final volume of the solution was 1000 cm3 (1.00 dm3).
In an experiment, a student found that 25.0 cm3 of this diluted phosphoric acid reacted completely with 30.00 cm3 of sodium hydroxide (NaOH\text{NaOH}NaOH) solution with a concentration of 0.100 mol/dm3.
The equation for the reaction is:
3NaOH+H3PO4→Na3PO4+3H2O 3\text{NaOH} + \text{H}_3\text{PO}_4 \rightarrow \text{Na}_3\text{PO}_4 + 3\text{H}_2\text{O} 3NaOH+H3PO4→Na3PO4+3H2OCalculate the amount, in moles, of sodium hydroxide in the 30.00 cm3 of sodium hydroxide solution.
Use your answer to (i) to calculate the amount, in moles, of phosphoric acid in the 25.0 cm3 of diluted acid.
Use your answer to (ii) to calculate the concentration, in mol/dm3\text{mol/dm}^3mol/dm3, of the diluted phosphoric acid.
Use your answer to (iii) to calculate the concentration, in mol/dm3\text{mol/dm}^3mol/dm3, of the original, concentrated phosphoric acid.
