(a) (i) A compound 'X' having two carbon atoms in its molecule turns blue litmus red and 5 – 8% solution of…
(a) (i) A compound 'X' having two carbon atoms in its molecule turns blue litmus red and 5 – 8% solution of 'X' in water is widely used as a preservative. Identify the compound 'X' and write its structure.
(ii) Compare its pH nature with a mineral acid.
(iii) 'X' on reacting with alcohols produces sweet smelling compounds, used in making perfumes. Name the reaction and write its chemical equation.
(iv) When sodium carbonate is added to 'X', a colourless gas is produced which turns lime water milky. Write the chemical equation for the reaction giving the name of the salt produced.
Solution
(a) (i) X- Ethanoic acid/ Acetic acid
[structural formula diagram of ethanoic acid: H-C(H)(H)-COOH] / CH3COOH
(ii) pH of 'X' will be higher than that of a mineral acid.
(iii) Esterification reaction
CH3COOH + CH3CH2OH —Acid⇌ CH3–COOCH2CH3 + H2O
(X)
(or reaction with any other alcohol)
(iv) 2CH3COOH + Na2CO3 → 2CH3COONa + CO2 + H2O
(X) Sodium acetate/sodium ethanoate
(balancing of equation is not mandatory)