JEE SPECIAL - संधारित्र | भौतिक विज्ञान | Ch - संधारित्र at 6 PM | Hindi Medium | Doubtnut

Explain the following : (a) Esters can be prepared by the reaction of RCOOH and R'X in basic medium. Why is this method not suitable for the preparation of t-butyl ethanoate ? (b) How is t-butyl ethanoate prepared ? ( c) Explain the rate esterification of the following acids with MeOH . (d) Why cannot HCl be used for the conversion of RCOOH to RCOCl ? ( e) Why can esters be prepared more efficiently by the squence : RCOOH rarr RCOCl rarr RCOOR' , rather than RCOOH rarr RCOOR' ? (f) Why are acyl azides less reactive than ROCOCl but a little more reactive than anhydride ? K_a of N_3 H = 2.6 xx 10^-5 and K_a of CH_3 COOH = 1.8 xx 10^-5 .

Aldehydes and ketones undergo nucleophilic addition reactions. With weak nucleophiles such as ammonia and its derivatives, (H_2 N-Z) , aldehydes and ketones react in weakly acidic medium to form compounds containing carbonnitrogen double bond with the elimination of water to form . Aldehydes can be easily oxidised to carboxylic acid on treatment with common oxidising agents like KMnO_4 K_2 Cr_2 O_7 , HNO_3 , etc. The carboxylic acid formed contain the same number of carbon atoms as the aldehydes. However ketones under drastic conditions with powerful oxidising agents undergo cleavage of C-C bond giving mixture of carboxylic acids having lesser number of C atoms than the original ketone. Arrange the following in the decreasing order of their reactivity towards HCN: HCHo , CH_3 COCH_3 , CH_3 CHO ,C_6 H_5 CHO

A white powder (A) on heating gave a non-combustible gas and a residue (B). The white compound A on reaction with H_(2)S in alkaline medium forms a precipitate (C ) which dissolves in dil. CH_(3)COOH . (B) can be disssolved in dil HCl to prepare a solution which gives a white precipitate with K_(4)[Fe(CN)_(6)] . Which of the following is true about B ?

A white powder (A) on heating gave a non-combustible gas and a residue (B). The white compound A on reaction with H_(2)S in alkaline medium forms a precipitate (C ) which dissolves in dil. CH_(3)COOH . (B) can be disssolved in dil HCl to prepare a solution which gives a white precipitate with K_(4)[Fe(CN)_(6)] . Compound A is

A white powder (A) on heating gave a non-combustible gas and a residue (B). The white compound A on reaction with H_(2)S in alkaline medium forms a precipitate (C ) which dissolves in dil. CH_(3)COOH . (B) can be disssolved in dil HCl to prepare a solution which gives a white precipitate with K_(4)[Fe(CN)_(6)] . Compuound B is

During the neutralisation of an acid by a base, the end point refers to the completion of reaction. The detection of end point in acid-base neutralisation is usually made by an acid-base indicator. An acid-base indicator is itself a weak acid (Phenolphthalein) or a weak base (Methyl orange). At 50% ionisation which depends on the medium. the anion furnished by an indicator (acid) cation furnished colour to solution at end point. For example, phenolphthalein dissociation underset("Colourless")(HIn)toH^(+)+underset("Pink")(In^(-)),K_(HIn)=([H^(+)][In^(-)])/([HIn]) is favoured in presence of alkali and pink colour of phenolphthalein ion is noticed as soon as the medium changes to alkali nature. The end point of acid-base neutralisation not necessarily coincides with eqivalence point but it is closer to equivalence point. Also at equivalence point of acid-base neutralisation, pH is not necessarily equal to 7. Which among the followig statements are correct? (P) At equivalence point of NaOH AND HCI,pH=7 (Q) At equivalence point of NaOH and CH_(3)COOH,pH gt 7 (R) At equivalence point of NH_(4)OH and HCI,pH lt 7 (S) An indicator shows best results if equivalence point is within the pH range pK_(In)pm1 (T) ) At equivalence point of NH_(4)OH and formic acid pH lt 7

Special Bonding Situation || Bonding in Electron Deficient Compound || Bridge Bond or Banana Bond || Examples OF Bridge Bonding BeH2, BeCl2, B2H6, Al2(CH3)6, Al2Cl6