JEE Advanced 2022 · Paper 1 · Chemistry Q8

ChemistryNumerical+3Question 44 of 54

If the reaction sequence given below is carried out with 15 moles of acetylene, the amount of the product D formed (in g) is _____.

The yields of A, B, C and D are given in parentheses.
[Given: Atomic mass of H = 1, C = 12, O = 16, Cl = 35]

Your answer

Answer and worked solution

Official answer: 135.8

The sequence.

A: three acetylene molecules trimerise in a red-hot iron tube to benzene. $15/3\times0.8=4$ mol.
B: Friedel-Crafts alkylation with n-propyl chloride. The carbocation rearranges, giving cumene. $4\times0.5=2$ mol.
C: the cumene process ( $\ce{O2}$ , then $\ce{H3O+}$ , losing acetone) gives phenol. $2\times0.5=1$ mol.
D: acetylation with $\ce{CH3COCl}$ /pyridine gives phenyl acetate, $\ce{C8H8O2}$ ( $M=136$ ). 1 mol.

So 136 g of D is formed.

JEE Advanced 2022 · Paper 1, Chemistry question 8