Question

3. In the titration of 10.000.04 ml of 0.104+0.002 M HCI, 23.02.10.04 ml of NaOH is required for neutralization. Calculate the Molarity of NaOH and indicate the uncertainty of the value. The pH of the solution is defined as; pH = -log[H] Where, [H*) is the molar concentration of H+. If the pH of the solution is 3.72 with an bsolute uncertantity of +0.03, what is the (H+) and its absolute uncertainty?

Answer 1

Volume He = 10.00 t 0.04 ml Molarity Ha = 00104 Z OO 002 M. I Volume Nao H = 23.02 € 0.04 ml At equivalence point, moles HCl = moles Naoh (Molarity X Volume) Hel (Molarity X Volume) Noon O. 104 M X 10ml = MNaor X 23.02 me O MNaOH = 0 o 104 M X loml 23.02 ML - MNOOH = 0.0451M To calculate Molarity only multiplication and division is done , so the relative uncertainty in Molarity can be calculated by adding relative uncertainty in volume and molarity Relative uncertainty = wlo.lou) + (Poy2 + (2004.)? = 0.000369 +0.000016+ 0.000016 - 10.00040 I = 0.02 Absolute uncertainty & Relative U x Molarity = 0.02 X 0.045 M. = 0.0009 M Molarity of NaOH = 0.0451 + 0.0009 M