posted by Jazz .
I have troubles with a titration of NaOH and HCl.
The volume of the HCl is 30 ml and its concentration is 0.1 mol per liter
The volume of the NaOH is 25 ml and the concentration is to be worked out. I understand that the reaction ratio for HCl to neutralize NaOH is 1:1.
But does that mean that 0.1 mol of HCl have to react with 0.1 mol of NaOH??? Can someone help me, PLEASE......
Yes, the ratio is 1:1 because of the equation.
HCl + NaOH ==> NaCl + H2O
It means 0.1 mol HCl and 0.1 mol NaOH react exactly; also it means that the moles NaOH must equal the moles of HCl at the equivalence point.
So if you started with 30 mL of 0.1 HCl, you started with M x L = 0.030L x 0.1 M = 0.003 moles HCl. Therefore, at the equivalence point, you must have added 0.003 mole NaOH. Since M = moles/L, 0.003/0.025 (the volume of NaOH) = 0.12 M for the NaOH. For titrations that are 1:1, it is simpler to use mL x M = mL x M
30 x 0.1 = 25 x M and solve for the unknown M.