Question 16 of 32advanced🔧 ApplyShort Answer2 marks

An alkene 'A' contains three C–C, eight C–H σ bonds and one C–C π bond. 'A' on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write IUPAC name of 'A'.

Correct Answer

The aldehyde with a molar mass of 44 u is ethanal (CH3CHOCH_3CHO). Since ozonolysis of alkene 'A' produces two moles of this aldehyde, 'A' must be a symmetrical alkene with four carbon atoms.

The structure of 'A' is CH3−CH=CH−CH3CH_3-CH=CH-CH_3. This structure contains three C–C σ\sigma bonds, eight C–H σ\sigma bonds, and one C–C π\pi bond, which perfectly matches the given conditions in the question.

Therefore, the IUPAC name of 'A' is But-2-ene.

Exercise: EXERCISES | Q: 9.6 | (Page Page 33)
For More Understanding

Explanation

The aldehyde with molar mass 44 u is ethanal (CH3CHOCH_3CHO). Ozonolysis of a symmetrical alkene yielding two moles of ethanal indicates the alkene is CH3−CH=CH−CH3CH_3-CH=CH-CH_3. This structure correctly accounts for the three C-C sigma bonds, eight C-H sigma bonds, and one C-C pi bond mentioned in the problem. The IUPAC name for this four-carbon alkene with a double bond at the second position is But-2-ene.

Solution Steps

  1. Step 1: Identify the aldehyde. The aldehyde with a molar mass of 44 u is ethanal (CH3CHOCH_3CHO).

  2. Step 2: Deduce the alkene structure. Since ozonolysis gives two moles of ethanal, the alkene must be CH3−CH=CH−CH3CH_3-CH=CH-CH_3.

  3. Step 3: Verify the bond counts. The structure CH3−CH=CH−CH3CH_3-CH=CH-CH_3 has three C-C σ\sigma bonds, eight C-H σ\sigma bonds, and one C-C π\pi bond.

  4. Step 4: Write the IUPAC name. The IUPAC name of CH3−CH=CH−CH3CH_3-CH=CH-CH_3 is But-2-ene.

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