Steel is heated to below red heat and then, cooled slowly. The process refers to
hardening
annealing
tempering
nitriding
Which of the following reagents converts both acetaldehyde and acetone to alkanes ?
Ni/H2
LiAlH4
I2/ NaOH
Zn-Hg/ conc. HCl
Which of the following can give a Grignard reagent when reacted with magnesium in dry ether?
C2H6
C2H5Cl
C2H5OH
C2H5CN
t-butyl chloride preferably undergo hydrolysis by
SN1 mechanism
SN2 mechanism
Any of (a) and (b)
None of these
The reaction,
C6H5CHO + CH3COOC2H5 C6H5CH = CHCOOC2H5 , is called
Benzoin condensation
Claisen condensation
Cannizaro's reaction
Perkin reaction
B.
Claisen condensation
The above reaction is known as Claisen condensation.
In this reaction, aromatic aldehyde condenses with esters having - hydrogen atoms, such as, ethyl acetate, in the presence of metallic Na and C2H5OH to form esters of - unsaturated acids.
C6H5CHO + H2CH - COOC2H5 C6H5CH = CHCOOC2H5 + H2O (ethyl cinnamate)
The best method to separate the mixture of ortho and para nitrophenol (1 : 1) is
vaporisation
colour spectrum
distillation
crystallisation
Iodoform gives a precipitate with AgNO3 on heating but chloroform does not because
C - I bond in iodoform is weak and C - Cl bond in chloroform is strong
chloroform is covalent
iodoform is ionic
None of the above
Which one of the following reactions is called Rosenmund reaction ?
Aldehydes are reduced to alcohols
Acids are converted to acid chlorides
Alcohols are reduced to hydrocarbons
Acid chlorides are reduced to aldehydes
During, acetylation of amines, what is replaced by acetyl group ?
Hydrogen atom attached to nitrogen atom
One or more hydrogen atoms attached to carbon atom
One or more hydrogen atoms attached to nitrogen atom
Hydrogen atoms attached to either carbon atom or nitrogen atom