Question

Consider the carbon compounds having following molecular formula:

(i) C₃H₆ (ii) C₃H₈ (iii) C₄H₆ (iv) C₆H₆ (v) C₆H₁₂

1. State the number of double covalent bonds present in C₃H₈.
2. Write the formula of first member of the homologous series to which the carbon compound C₄H₆ belongs.
3. Which one of the above compounds forms a ring structure of carbon atoms?
4. Identify, which of the above compounds, is a member of alkane series.

Answer 1

(a) There are nine covalent bonds.

(b) C₄H₆ is an alkyne, The alkynes are a group of chemical compounds with carbon and hydrogen at least one triple bond. With a general molecular formula of C_n H_2n-2, where n is any integer higher than 1, the group of compounds is a homologous series.
The first member of this homologous series is ethyne (C₂H₂). 
\[\ce{H - C = C - H}\]

(c) C₆H₆ (Benzene) will form the ring. The structure features triple-alternate double bonds and a six-carbon ring, which is symbolised by a hexagon.

(d) C₃H₈ is an alkane as it has each carbon bonded to four other atoms through single covalent bonds and follow general formula C_n H_2n+2.