1. CHEM LAB
Exam Tips 2.ppt

2. SODIUM FUSION(LASSAIGNES) TEST
THE ORGANIC COMPOUND TO BE TESTED IS FUSED WITH METALLIC SODIUM.IN THIS WAY SODIUM CYANIDE,SODIUM SULPHIDE AND/OR SODIUM HALIDES IS FORMED WHICH CAN BE READILY IDENTIFIED.

3. TEST FOR NITROGEN
THE CYANIDE FORMED CAN BE DETECTED BY PRUSSIAN BLUE TEST.
STEP 1: FESO4 + 6NACN=Na4[Fe(CN)6]+Na2SO4
STEP 2: 3Na4[Fe(CN)6] + 2Fe2(SO4)3=Fe4[Fe(CN)6]3(PRUSSIAN BLUE)+6Na2SO4

4. TEST FOR SULPHUR THIS IS TESTED AS SULPHIDE TEST 1:
THE COMPOUND IS TREATED WITH DIL. ACETIC ACID AND THEN WITH LEAD ACETATE.
A BLACK PRECEPATE OF LEAD ACETATE INDICATES THE PRESENCE OF SULPHUR
TEST 2:
THE COMPOPUND IS TREATED WITH DIL.SOLN. OF Na2[Fe(CN)5NO] A PURPLE COLOURED COMP. OF Na4[Fe(CN)5NOS] IS FORMED INDICATING THE PRESENCE OF SULPHUR.

5. TEST FOR HALOGENS COLOUR SOLUBILITY IN Aq. Ammonia HALOGEN WHITE
COMPLETELY SOLUBLE Cl
PALE YELLOW
PARTIAL SOL. Br
YELLOW
IN SOLUBLE. I
THE FUSION SOLN IS ACIDIFIED WITH DIL.HNO3 AND THEN EXCESS OF AgNO3 IS ADDED.

6. _OH (ALCOHOLIC) TEST 1::SODIUM TEST 2ROH+2Na=2RONa+H2(GAS)
TEST 2:: ACETYL CHLORIDE TEST
acetyl chloride reacts vigorously with primary and secondary alcohols with evolution of HCl.
HCl +NH4OH =NH4Cl(WHITE FUMES)+ H2O

7. PHENOL GIVES VIOLET COLOUR WITH FeCl3 SOLN.
FeCl3+6C6H5OH= [Fe(OC6H5)6]-3+3HCl

8. CARBONYL TEST FOR ALDEHYDES AND KETONES.
2,4-DINITROPHENYL HYDRAZINE-TEST
-> FORMATION OF CRYSTALLINE PRECIPITATE WITH THE REAGENT INDICATES THE PRESENCE OF ALDEHYDES AND KETONES.

9. SPECIFIC FOR ALDEHYDES
SCHIFF’S TEST
->APPEARANCE OF PINK RED OR MAGENTA COLOR WITH REAGENT.
TOLLEN’S TEST ->SILVER MIRROR WITH REAGENT(Ag+).
FEHLING’S TEST ->RED PRECIPITATE OF Cu2O WITH ALDEHYDE GROUP.

10. CARBOXYLIC GROUP LITMUS TEST (BLUE TO RED).
SODIUM BICARBONATE TEST(NaHCO3).CO2 MOVES OUT FROM NaHCO3.
ESTER TEST: REACTS WITH ALCOHOL TO GIVE SWEET SMELLING COMPOUND(ESTER).

11. ALIPHATIC AMINO GROUP WITH HNO2 PRIMARY GROUP GIVES ALCOHOL
WITH HNO2 SEC GIVES NITROSOAMINES YELLOW OILY LIQUID(R2N-NO).
WITH HNO2 TERTIARY GROUP GIVES TRIALKYLAMMONIUM NITRITE (R3 N+ HONO-)

12. AROMATIC AMINES
WITH HNO2 PRIMARY GIVES BENZENE DIAZONIUM CHLORIDES(PhN2+ Cl-).
SECONDARY GROUP GIVES N-ALKYL-N-PHENYL NITROSOAMINE.
TERTIARY GROUP GIVES P-NITROSOANILINE.

13. SPECIFIC FOR PRIMARY AMINE(ALI+ARO) UNPLEASANT ODOUR OF ISOCYNIDE(RNC) WITH CHLOROFORM+KOH.

14. NITRO GROUP
THE PRESENCE OF NITRO GROUP CAN BE DETYECTED BY REDUCING THE COMPOUND WITH Sn/HCl AND THEN CONDUCTING CARBYL AMINE TEST.