Attempt either (a) or (b) : (a) (i) What is homologous series ? Which two of the following organic compounds…
Attempt either (a) or (b) :
(a) (i) What is homologous series ? Which two of the following organic compounds belong to the same homologous series ?
C2H4, C4H10, C3H4, C4H8
(ii) Write the product(s) in the following reactions :
(I) CH3–CH2–OH + CH3COOH $\xrightarrow{\text{Acid}}$
(II) C2H5OH + O2 $\xrightarrow{\text{Burning}}$
(iii) Why does micelle formation take place when soap is added to water ?
Solution
(a) (i)
• A series of compounds in which the same functional group
substitutes for hydrogen in a carbon chain. / Can be
represented by a single general formula and successive
members differ by -CH2 unit or 14u.
• C2H4 and C4H8 belong to the same homologous series/ are
alkenes.
Acid
(ii) (I) CH3 CH2 OH + CH3 COOH → CH3 COOC2 H5 + H2 O
Burning
(II) C2 H5 OH + 3O2 → 2CO2 + 3H2 O
(balancing may be ignored)
(iii) The ionic end of soap interacts with water while the carbon chain
interacts with oil/dirt. The soap molecules thus form a structure
called micelle.
OR
(b) (i) (I) Propanone/acetone
(II) Propyne
(ii) Hydrogenation/addition reaction.
(iii) C4H10 will have higher melting point, as it has a higher molecular
mass than C3H8 and melting point increases with the increase in
molecular mass.
(iv) Sodium ethoxide (C2H5ONa) is formed and hydrogen gas is
evolved.
/
(balancing may be ignored)
(v) CH3COON C2H5 + NaOH →CH3COONa + C2H5OH
½+ ½
SECTION – C
(Physics)
