Four solutions of unknown HCl concentration are titrated with solutions of NaOH. The following table lists the volume of each unknown HCl solution, the volume of NaOH solution required to reach the equivalence point, and the concentration of each NaOH solution. Calculate the concentration (in M) of the unknown HCl solution in each case.

HCI Volume (mL) |
NaOH Volume (mL) |
[NaOH] (M) |

(a) 25.00 mL |
28.44 mL |
0.1231 M |

(b) 15.00 mL |
21.22 mL |
0.0972 M |

(c) 20.00 mL |
14.88 mL |
0.1178 M |

(d) 5.00 mL |
6.88 mL |
0.1325 M |

Step 1 of 6

Solution: Here, we are going to calculate the concentration of the unknown \(\mathrm{HCl}\) solution.

Neutralisation reaction is the reaction between an acid and a base to give salt and water. The neutralization reaction in the given problem is:

\(\mathrm{NaOH} \text { (aq) }+\mathrm{HCl} \text { (aq) } \rightarrow \mathrm{H}_{2} \mathrm{O} \text { (1) }+\mathrm{NaCl} \text { (aq) }\)

Here, 1 mole of \(\mathrm{HCl}\) requires 1 mole of \(\mathrm{NaOH}\) for complete neutralization.