Bleaching of dyes. Dem. 616

Reference: WOLF, AI. G., AND RAPP, G., 33, 414. (1956). Dem. 6 17-Bleaching versus Solvent Action. Experimeut devised bg Raymond P. Carman. To shozc: ...
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Tested Overhead Proiection Series Compiled by HUBERT N. ALYEA

Princeton University

20. GROUP VIII. THE HALOGENS

Procedure: Label each plastic strip with its respective fluid, e.g., INDIA I R K , MAGIC MARICER, etc. Project C-4 half-full of bleaching solution. Immerse the strips for 5 min. Compare extent of bleaching.

2. CHLORIDES

Observation: Inks containing graphite or carbon (e.g., India Ink, pencil, some ball-point inks) will not bleach; vegetable dyes often bleach).

Dem. 6 13-Hydrolysis

To shoa:

of FeC18

Thermally accelerated hydrolysis.

Procedure: I'roject H-3 with two oval tubes quarterfull of I'eCIJ-aq of equal concentration. Heat onc.

+

-

+

3H,O Fe(OH), 3 HCI. Observations: I"eC13 At first dark yellow ferric hydroxide forms, and then this forms rcd colloidal fcrric hydroxide sol.

Dem. 6 14-Hydrolysis

of TiCL

To show: Formation of TiO? from hydrolysis of TiClr in the air. Alate~ials: Bottle of TiCI,, two-hole stopper with glass tubing inserted; 1-ft length of rubber tubing on one.

Dem. 6 16-Bleaching

of Dyes

Experiment developed by Raymond P. Garman. To show: The bleaching of a dye (methyl violet) by chlorine-aq. Materials: Methyl violet, 6 X 3-in. strip of cellophane dipped into methyl violet-aq and dried; C-1, bleaching solution made up in one of the following ways. (a) Add dilute HCI t o Chorox until faintly acid, then filter and use the clear solution. (0) Mix hypochlorite bleaching powder with 3 times its volume of HzO; filter, use the clear solution. (c) Bubble Cl, gas into H20.

Procerlure: (a) Place bottlc of TiCL on vertical stage. Rcmovc st,opper. (0) Insert rubber stopper with tuhing in bott,le of TiCl,; blow through rubber tubing.

P~ocedure: Project C-1 colored strip into it.

Observalioiis: (a) Smolie pours from the bottle opcn to the air. (b) A jet of smokc issues from the tubing.

Obsewations: The half which dips into the CIz-aq is bleached; the upper half remains violet.

-

+ 4H10 in air + 2H2O.

Reactions: TiCl, Ti(OH), TiO, smoke

-+

Ti(OH),

+ 4HC1.

Note: Skywriling can be done with this; NHa is also ejected nnd unites with ihe HCI lo form white N H O smoke. Smoke sweena sro also made with fine particles of heated hydruearb~m uils.

Reference: (1956).

filled with CIS-aq. Dip the

WOLF, A I . G.,

Dem. 6 17-Bleaching

AND

RAPP, G., 33, 414

versus Solvent Action

Experimeut devised bg Raymond P. Carman To shozc: Difference between bleaching action and solvent action on two differenttypes of inks.

3. HYPOCHLORITE (Bleaching) Dem. 6 15-Bleaching

of Ink

Experiment developed by Raymond P. Carman To show: Bleaching action of chlorine on various inks and dyes. Bleachzng solution: N a d e up in any of the following ways. (a) Bubble chlorine gas into water. (b) Nix hypochlorite bleaching powder with three times its volurnc of water; filter, use the clear solution. (c) Add dil. HCI to Chlorox or otherblearhingsolution until faintly arid; filter and use clear solution. Materials: Rlcaching solution; India ink, ordinary hluc writing ink, Magic Alarlier, vegetable dye, ballpoint pen, pencil, grcase pencil, etc. Clear plastic in. Ccll C-4. stri[is, (iX a/n X

Afaterials: Ball-point pen, ordinary writing ink; C-2, two G X a/a X '/a-in. strips of plastic; clear chlorine water or the hypochlorite described in preceding demonstrat,ion; isopropyl alcohol. Procedure: Write BALLPOINT and OIZDINARY INK with the respective inks. Project C-2 with cell one 2 / a full of dilute chlorine water, and cell two 2/3 full of isopropyl alcohol. (a) Drop the ball-point ink strip into cell 1, and the other strip into cell 2 . I'roject for 2 min. (b) Now interchange the strips. Obsewations: (a) Some Ball-point inks are not affected by bleaching solution; the ordinary ink is not affected by the alcohol. (b) Upon interchanging, chlorine bleaches the ordinary ink, and alcohol dissolves the ball-point ink. Volume 46, Number 5, May 1969

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A355