(Considering that all isomers satisfy the given conditions) Since given compound produces pink colour with neutral FeCl3. So, it must have at least one –OH group attached to benzene ring.
Also, given compound is optically active, it means it should have a chiral centre, which is only possible when it has –CH(OH)CH3.
DBE (Double bond equivalent) of C8H10O2 is
= \(\text{Number of carbon atoms} - \left(\frac{\text{Number of monovalent atoms}}{2}\right) + 1\)
= \(8 - \frac{10}{2} + 1 = 4\)
So, total isomeric structures = 6
Find the least horizontal force \( P \) to start motion of any part of the system of three blocks resting upon one another as shown in the figure. The weights of blocks are \( A = 300 \, {N}, B = 100 \, {N}, C = 200 \, {N} \). The coefficient of friction between \( A \) and \( C \) is 0.3, between \( B \) and \( C \) is 0.2 and between \( C \) and the ground is 0.1.
Let $ S $ denote the locus of the point of intersection of the pair of lines $$ 4x - 3y = 12\alpha,\quad 4\alpha x + 3\alpha y = 12, $$ where $ \alpha $ varies over the set of non-zero real numbers. Let $ T $ be the tangent to $ S $ passing through the points $ (p, 0) $ and $ (0, q) $, $ q > 0 $, and parallel to the line $ 4x - \frac{3}{\sqrt{2}} y = 0 $.
Then the value of $ pq $ is