Alkanes Flashcards
Methane Cannot be prepared by which 4 methods?
Wurtz Reaction, Sabatier-Senderen’s reaction, Kolbe’s reaction, Frankland’s Reaction
Reactivity order of halogens? Which halogen doesn’t given formation of alkanes from alkyl halides
Fluorine>Iodides> Bromides> Chlorides. Florine doesn’t show due to strong bond showing low dissociation
Give Wurtz Reaction
Ch3Br + 2na + brch3 GIVES{DRY ETHER} ch3-ch3 + 2nabr
(A)Reactions that give only symmetrical alkanes .(B)Which one give unsymmetrical as well as symmetrical?
(A)Wurtz, (B) Corey House
(A)Name all catalysts involved un decarboxylation of carboxylic acids?
(B)Specialty of this reaction wrt to formed carbon compound?
(C) Another name for this reaction?
(A)NAOH, Cao to keep NAOH dry due to it’s hygroscopic nature, Heat
(B) Alkanes formed contain one carbon less than original
(C) Soda lime decarboxylation
Write Kobe’s Electrolytic method.
2CH3COOH-NA+ + 2H2O GIVES{ELECTROLYSIS} CH3CH3 + 2CO2 + H2 + 2NAOH
2 Reaction which transforms aldehydes and ketones to alkanes? Also give it’s catalysts.
Clemmensen Reduction and Woff kishner reduction. Amalgamated zinc-Hg and conc. HCL for Clemmesoon reduction. First step loses 1H2Oand second step C2H5ONA or NOAH and heat for Woff kishner and also hydrazine(Not catalyst)
Tip: Basically number of oxygen-carbon bonds broken, that much number of hydrogen will be added in it’s place.
Catalyst in Frankland’s reaction? Also give its rn
Ether which is an inert solvent
General formula of Grignard reactions. Catalysts?
R-Mg-X. Undergoes hydrolysis in presences of acid or reacts with ammonia(HNH2 or NH3), alcohols or amines having active hydrogen atom to give alkane corresponding to alkyl group of Grignard reagent
Does eicosane or decane have higher MP?
Decane(C10H22) has higher MP than Eicosane(C20H42)
Why do alkanes show low reactivity towards acids, bases, oxidizing and reducing agents?
Non polar nature and absence of pi bond
Halogenation Conditions:
High temp(300C to 500C) or in presence of Sunlight or UV rays. The extent of halogenation depends on amount of halogen used
Halogens that have special cases when doing halogenation reaction for alkanes.
Fluor9nes react violently while Iodination is very slow and reversible and so iodination is carried out in presence of oxidizing agent of HIO3.
When incomplete combustion(Insufficient amount of air) of alkanes occur, what is formed? What is it’s uses?
Carbon black. Used for manufacture of ink, printer ink, black pigments and filters
Molecular formula of Iodic acid
HIO3