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5. Warm with NaOH.

Alcohol evolved Esters.

NHj evolved ... ... ... Amides.

Brown coloration Dextrose, lactose, maltose.

Amine evolved Salts of amine.

Red colour Formates.

Precipitates yellow solid on

boiling . Acetates.

Yellow precipitate in cold ... Succinates.

Prussian blue Ferrocyanides.

7. Add Fehling's solution.

Reduction on warming ... Dextrose, lactose, aldehydes.

Reduction on prolonged boiling Glycerol, acetone.

I 8. Add bromine water.

Decolorised Unsaturated compounds; e.g.,

\ allyl alcohol.

9. Warm gently with a solution of silver oxide in weak ammonia.

\ Immediate precipitation of Ag Formaldehyde.

'Silver mirror Acetaldehyde, dextrose, lactose, tartrates.

10. Test neutral solution with CaCl2.

White precipitate insoluble

acetic acid Oxalates.

White precipitate on boiling ... Citrates.

White precipitate on shaking Succinates.
White precipitate soluble

acetic acid Tartrates.

TESTS FOR THE ELEMENTS,f AND CONCLUSIONS THEREFROM

Fuse with excess Na in dry tube. Heat to redness, and drop into boiling-tube containing water. Filter. Test filtrate as follows:

a. To portion add sodium nitroprusside solution. Violet coloration indicates S.

/3. Place a drop of filtrate on silver coin. Black stain indicates S.

* Make neutral, if acid, by adding NH4OH, and boiling off excess. Make neutral, if alkaline, by adding HC1.

.f It is assumed here that C and H are present.

y. To portion add NaOH and FeS04 solutions; warm; add FeCl3; acidify with HC1. Green colour or blue precipitate indicates N. \ S. To portion add concentrated HNO8; boil for few minutes *; add WgNOa.

1 White precipitate, soluble easily in NH4OH, indicates CI.

I Yellow precipitate, soluble sparingly in NH4OH, indicates Br.

I Yellow precipitate, insoluble in NH4OH, indicates I.

NITROGEN ONLY

Amide, amine, ammonium salt, ferrocyanide, ferricyanide, cyanide, nitrite, nitrate of a base.

HALOGEN ONLY
Alkyl halide, iodoform, chloroform, chloracetic acids.

NITROGEN AND HALOGEN TOGETHER

Haloid salt of an amine or base, or an ammonium salt of chloracetic acid.

SULPHUR ONLY

Ethyl hydrogen (K or Na), sulphate, bisulphite compounds, Buiphonal.

SULPHUR AND NITROGEN TOGETHER Sulphate of amine or base, thiourea, thiocyanate.

NOTES ON TESTING FOR ELEMENTS

1. Use excess of Na, and heat to redness, so as to prevent preferential formation of sodium sulphide (if S is present) to sodium cyanide.

2. When testing for halogens, boil with concentrated HN03, to drive off HCN if N is present.

3. Copper wire-test for halogens (to be used always for confirming halogens) is useless if acids or salts of bases are present—e.g., urea nitrate gives the green coloration.

MELTING-POINT

Always repeat determination of melting-point; but heat more slowly in the neighbourhood of the melting-point, so as to get a more accurate reading.

Many metallic salts do not melt; also starch and some sugars char; oxamide decomposes and does not melt; melting-points are affected considerably by traces of moisture and impurity.

* To destroy cyanides, if N is present.

BOILING-POINT

In the case of a liquid the boiling-point is of value. It can be determined in the simple apparatus shown in the figure, when the side-tube of the small distilling-bulb acts as condenser.

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1908 SYLLABUS OF THE BOARD OF EDUCATION EXAMINATION IN PRACTICAL ORGANIC CHEMISTRY

Detection for carbon, hydrogen, and nitrogen in organic compounds.

Determination of boiling-points and of melting-points.

Reactions of and tests for the following bodies, which will be supplied either in the pure state or in aqueous solution, or (if acidic or basic) in the form of salts:

Methyl and ethyl alcohols, chloroform, iodoform, ethyl iodide, ethyl bromide, ethyl acetate, ethyl hydrogen sulphate, acetaldehyde, formaldehyde, acetone; acetic, formic, tartaric, oxalic, citric, hydrocyanic, ferrocyanic, and ferricyanic acids; acetamide, ethylamine, glycerol, urea, cane-sugar, glucose, lactose, and starch.

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