Organic 2 Review Problem 474

Organic 2 Review Problem 474 - 458 PRACTICAL O RGANIC C...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
458 PRACTICAL ORGANIC CHEMISTRY Transfer 25 ml. of this dilute solution by means of a pipette to a conical flask, and add similarly 50 ml. of Aljio iodine solution. Now add io% sodium hydroxide solution until the liquid becomes pale yellow in colour, and allow the solution to stand, with occasional shaking, at room temperature for at least io minutes. Then acidify with dilute hydrochloric acid (free from chlorine) in order to liberate the remaining iodine. Titrate the latter with Mlio sodium thiosulphate solution, using starch as an indicator in the usual way. From the above equations, it will be seen that i ml. of theM/io iodine solution used in the oxidation is equivalent to 0-00150 g. of formaldehyde. Example of Calculation. Weight of formalin solution used . . . 2-520 g. Diluted to 500 ml. 50 ml. of Af/io I 2 solution added to 25 ml. of this dilute formalin solution. After oxidation in the presence of sodium hydroxide, and subsequent acidifica- tion, the excess of iodine liberated required 17-3 ml. M/io Na
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

Ask a homework question - tutors are online