Qualitative Analysis of a Single Solid Organic Compound

B.Sc. HONOURS PRACTICAL MANUAL(3 rd Year  Year)) CHP: 34b Exper!e"# $: %&a'#a#e A"a'** +, a S"-'e S+'d Or-a"c C+!p+&"d Sa!p'e N&!ber: P*ca' Carac#er*#c*: i) C+'+r:

ii) Tex#&re:  

iii) Od+r:

/e#ec#+" +, Speca' E'e!e"#* (N0 C'0 S) b La**a-"e1* !e#+d: s odium was taken in a fusion tube and heated gently until La**a-"e1* La**a-"e 1* Te*# Te*# : A pea sized dry and clean sodium it melted with a shiny surface. A pinch of the sample was added to it and the mixture was heated gently and then strongly to red hot on a non-luminous flame for about two minutes. Finally the fusion tube was carefully plunged in a mortar containing distilled water  (-!"  (-!" m#). $he mixture was ground thoroughly by a pestle and filtered. $he following experiments were performed with this a%ueous colorless filtrate:

E2PERIMENT Te*# ,+r N#r+-e": $o a portion of the filtrate& a few crystals of Fe'  were added. (Alternati*ely freshly prepared Fe'  solution may also be added.) $he mixture was  boiled gently and then acidified with dil. +,'. Te*# ,+r S&',&r  : $o a portion of the filtrate& !-, drop of dilute sodium nitroprusside solution was added. Te*# ,+r a'+-e"* (If N and/or S absent) : A portion of the filtrate was acidified with concentrated + / and Ag/ solution was added. $o the precipitate dilute + + was added.

 If N and/or S present : A portion of the filtrate was acidified with dil. +/ and gently boiled till the volume of the solution becomes half . 0t was then cooled and Ag/ solution is added. $o the precipitate dilute + + was added.

OBSERATION

INERENCE

A deep blue solution or precipitate

itrogen present

'ulfur present urple coloration 1urdy white precipitate. 1hlorine present

'oluble& but reappeared on acidification with dil. + /.

'ame inference as abo*e

'ame obser*ation as abo*e

'ame inference as abo*e

U*e +, 5" 6 Na 7CO3 !x#&re "*#ead +, !e#a''c Na 8Mdd'e#+"1* #e*#9

2An intimate mixture of 3n dust and a ,1/ (, : / by weight) may be stored in a bottle.4 A pinch of organic sample and the abo*e mixture (,"" mg) was heated gently and then strongly to red hot on a non-luminous flame for about three minutes. $hen the fusion tube was plunged in a mortar  containing distilled water  (5-6 m#). $he mixture was ground thoroughly by a pestle and filtered. $he following experiments were performed with this a%ueous filtrate: 27hen an organic compound is heated with a mixture of zinc powder and a ,1/& the nitrogen and chlorine are con*erted into a1 and a1l respecti*ely& and the sulphur into 3n' (insoluble in water). a1 and a1l are extracted with water and detected as in La**a-"e1* !e#+d& whilst 3n' in the residue is decomposed with dilute +1l and + ,' e*ol*ed is identified with lead acetate paper  which forms black b'.4 S+'&b'# C'a**,ca#+": Ob*era#+"* #+ be !ade a# r++! #e!pera#&re (scale: !"" mg of sample in / m# of sol*ent) a#er

;< HC'

;< NaOH

;< NaHCO3

8







 

8

;

;

 



8

8

olar compound: low 97 aliphatic acids&  polyphenols& salts. a%. Cthanol (/ m#) was added. $he mixture was boiled gently in a water   bath for B minutes and then filtered into freshly  prepared $ollensD reagent (, m#). Te*# ,+r a!de (@CONH 7) a"d !de: A mixture of the sample (B" mg)& a a+ = E+  pellet and a few drops of water was heated strongly.

OBSERATION

INERENCE

@ed = orange azo-dye

Aromatic  +, present

@ed = orange azo-dye

Aromatic  , present

A grey = black precipitate or sil*er mirror

Aromatic  , present

'mell of +/ was percei*ed and the e*ol*ed *apour turned  phenolphthalein paper temporarily pink.

Amide or  imide present

 Preparation of -ollens’ rea&ent, &N% ( !+$%/  % fe! drops of diute Na&H soution are added to '-2  of %*N& + soution. ,e resutin* precipitate is ten dissoed by addin* reuisite aount of NH 0&H soution.

Te*#* ,+r "+""#r+-e"+&* ,&"c#+"a' -r+&p*: (pe"+'c@OH0 CO0 @COOH)

E2PERIMENT Te*# ,+r carb+x'c acd (@COOH): 'ample or its alcoholic solution was added to a saturated solution of a+1 /.

OBSERATION Cffer*escence was obser*ed

 1sterification: A solution of the sample in 1haracteristic fruity dehydrated alcohol (, m#) and , drops of conc. smell of ester was +,' was warmed on a water bath for B minutes. 0t  percei*ed. was cooled and then poured cautiously in a beaker containing B> solution of a+1 / (!"-!B m#). Te*# ,+r carb+"' (CO +r @CHO) (adeyde  #etone) : ,&-initrophenylhydrazine () reagent ( a, solution was added under ice cold condition. $he resulting solution was then added to cold alkaline solution of the sample. 5%ny one of te aboe tests if positie t at indicates te presence of penoic –&H *roup. ,o so! te absence of penoic –&H6 bot tests ust be  perfored.7

ermanent or transient henolic + group  purple = red = blue = green  present. coloration @ed precipitate or coloration of azo dye obser*ed.

henolic + group  present.

 5%ccordin* to te syabus6 o!eer6 &N8 &N1 ,1S, 9&R 1%:H 9;N:,I&N%