Identify the homologous series to which A, B and C each belong. Define isomerism. Suggest which of the compounds will exhibit isomerism. Draw two structures of the isomers. Write an equation for the c

Here's the solution to question 4:

a) Identify the homologous series to which A, B and C each belong

• A: $\text{C}_2\text{H}_6$ fits the general formula $\text{C}_n\text{H}_{2n+2}$. It is an $\boxed{\text{alkane}}$.
• B: $\text{C}_2\text{H}_7\text{OH}$. This formula is chemically incorrect. Assuming it is a typo for $\text{C}_2\text{H}_5\text{OH}$ (ethanol), it belongs to the $\boxed{\text{alcohols}}$ homologous series.
• C: $\text{C}_2\text{H}_4$ fits the general formula $\text{C}_n\text{H}_{2n}$. It is an $\boxed{\text{alkene}}$.

b) i) Define isomerism
Isomerism is the phenomenon where compounds have the same molecular formula but different structural formulas or arrangements of atoms in space.

b) ii) Suggest which of the compounds will exhibit isomerism
Given the instruction to draw isomers, and assuming the molecular formula for compound B is $\text{C}_2\text{H}_6\text{O}$ (correcting the typo in $\text{C}_2\text{H}_7\text{OH}$), then compound $\boxed{\text{B}}$ will exhibit isomerism.

b) iii) Draw two structures of the isomers in b(ii)
For the molecular formula $\text{C}_2\text{H}_6\text{O}$, the two isomers are:

1. Ethanol (an alcohol): $$\text{CH}_3\text{CH}_2\text{OH}$$
2. Methoxymethane (an ether): $$\text{CH}_3\text{OCH}_3$$

c) Write an equation, stating reaction condition, for the conversion of C to A
This is the hydrogenation of ethene (C) to ethane (A).

• Equation: $$\text{C}_2\text{H}_4\text{(g)} + \text{H}_2\text{(g)} \rightarrow \text{C}_2\text{H}_6\text{(g)}$$
• Reaction condition: $\boxed{\text{Nickel catalyst, 150-200°C}}$ (or Platinum/Palladium catalyst at room temperature).

d) Describe a simple chemical test for B
Assuming B is ethanol ($\text{C}_2\text{H}_5\text{OH}$), a simple chemical test is:

• Add acidified potassium dichromate(VI) solution to the compound.
• Observation: The orange solution will turn $\boxed{\text{green}}$ in the presence of ethanol, as the alcohol is oxidized.