Q73 of 312 Page 266

An organic compound A (molecular formula C2H4O2) reacts with Na metal to form a compound B and evolves a gas which burns with a pop sound. Compound A on treatment with an alcohol C in the presence of a little of concentrated sulphuric acid forms a sweet-smelling compound D (molecular formula C3H6O2). Compound D on treatment with NaOH solution gives back B and C. Identify A, B, C and D.

A is ethanoic acid (CH3COOH) ; B is sodium ethanoate (CH3COONa); C is methanol (CH3OH) and D is methyl ethanoate (CH3COOCH3).

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71 An organic acid X is a liquid, which often freezes during winter time in cold countries, having the molecular formula C2H4O2. On warming it with methanol in the presence of a few drops of concentrated sulphuric acid, a compound Y with a sweet smell is formed.

(a) Identify X and Y. Also write their formulae showing the functional group present in them.


(b) Write a chemical equation for the reaction involved.

 72 An organic compound A having the molecular formula C3H8O is a liquid at room temperature. The organic liquid A reacts with sodium metal to evolve a gas which bums causing a little explosion. When the organic liquid A is heated with concentrated sulphuric acid at 170 �C, it forms a compound B which decolourises bromine water. The compound B adds on one molecule of hydrogen in the presence of Ni as catalyst to form compound C which gives substitution reactions with chlorine.

(a) What is compound A?


(b) What is compound B?


(c) What type of reaction occurs when A is converted into B?


(d) What is compound C?


(e) What type of reaction takes place when B is converted into C?

 74 Which of the following hydrocarbons can decolourise bromine water and which cannot? Why?

C6H12, C6H14, C6H10

 75 A four carbon atoms containing neutral organic compound X reacts with sodium metal to evolve a gas which burns with a 'pop' sound. Another four carbon atoms containing carbon compound (Y) reacts with sodium hydrogencarbonate to evolve a gas which turns lime water milky. When compounds X and Y are heated together in the presence of a little of concentrated sulphuric acid, then a new compound Z is formed.

(a) What is compound X? Also write its formula.


(b) What is compound Y? Also write its formula,.


(c) What is compound Z? Also write its formula.


(d) What type of smell is given by compound Z?


(e) What is the general name of compounds like Z?


(f) What is the general name of the reaction which takes place between X and Y to form Z?