Attempt either option (A) or (B) : (A) (i) Carbon cannot form C4+ cation and C4– anion. Explain. (ii) Define…
Attempt either option (A) or (B) :
(A) (i) Carbon cannot form C4+ cation and C4– anion. Explain.
(ii) Define homologous series of carbon compounds. Why are the melting and boiling points of C4H10 higher than C3H8 or C2H6 ?
(iii) What happens when ethanol is heated with acidified potassium dichromate ? [2+2+1]
Solution
(A)
(i) Carbon cannot form C4+ cation because removal of four electrons is
energetically not possible. Carbon cannot form C4− anion because nucleus
with six protons cannot hold ten electrons.
(ii)
• A series of compounds in which the same functional group substitutes
for hydrogen in carbon chain is called a homologous series.
• Because of higher molecular mass of C4H10 than C3H8 or C2H6.
(iii) /
Ethanoic acid / acetic acid CH3COOH is formed /
acidified K2Cr2O7 +Heat
CH3-CH2OH → CH3COOH
OR
(B)
(i) I. Propanal
II. Propyne
(ii) I. Ester group
II.
(iii) Soaps reacts with calcium and magnesium salts present in hard water
to form scum (insoluble substance).
SECTION – C
Physics