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(A) (i) Carbon cannot form $\ce{C^4+}$ cation and $\ce{C^4-}$ anion. Explain.
(ii) Define homologous series of carbon compounds. Why are the melting and boiling points of $\ce{C4H10}$ higher than $\ce{C3H8}$ or $\ce{C2H6}$?
(iii) What happens when ethanol is heated with acidified potassium dichromate ?
(ii) Define homologous series of carbon compounds. Why are the melting and boiling points of $\ce{C4H10}$ higher than $\ce{C3H8}$ or $\ce{C2H6}$?
(iii) What happens when ethanol is heated with acidified potassium dichromate ?
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(i) Carbon cannot form $\ce{C^4+}$ cation because removal of four electrons is energetically not possible. Carbon cannot form $\ce{C^4-}$ anion because nucleus with six protons cannot hold ten electrons. (2 Marks)
(ii) • A series of compounds in which the same functional group substitutes for hydrogen in carbon chain is called a homologous series. (1 Mark)
• Because of higher molecular mass of $\ce{C4H10}$ than $\ce{C3H8}$ or $\ce{C2H6}$. (1 Mark)
(iii) Ethanoic acid / acetic acid / $\ce{CH3COOH}$ is formed /
$\ce{CH3-CH2OH ->[Alkaline KMnO4 + Heat][Or acidified K2Cr2O7 + Heat] CH3COOH}$ (1 Mark)
(ii) • A series of compounds in which the same functional group substitutes for hydrogen in carbon chain is called a homologous series. (1 Mark)
• Because of higher molecular mass of $\ce{C4H10}$ than $\ce{C3H8}$ or $\ce{C2H6}$. (1 Mark)
(iii) Ethanoic acid / acetic acid / $\ce{CH3COOH}$ is formed /
$\ce{CH3-CH2OH ->[Alkaline KMnO4 + Heat][Or acidified K2Cr2O7 + Heat] CH3COOH}$ (1 Mark)