Question

If the molar mass of C and D formed is X and Y respectively, then the value of $\frac{Y-X}{7}$ is

• A. 6
• B. 7
• C. 8
• D. 9

Answer 1

Answer: (A)

6

Answer 2

The first pathway yields but-2-enal ($\text{C}_4\text{H}_6\text{O}$), with molar mass X = 70 g/mol. The second pathway yields 4-methylpent-3-en-2-one ($\text{C}_7\text{H}_{12}\text{O}$), with molar mass Y = 112 g/mol. Therefore, $\frac{\text{Y}-\text{X}}{7} = \frac{112-70}{7} = \frac{42}{7} = 6$.