Complete the following reactions by writing the structure of the main products:
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
Let $ y(x) $ be the solution of the differential equation $$ x^2 \frac{dy}{dx} + xy = x^2 + y^2, \quad x > \frac{1}{e}, $$ satisfying $ y(1) = 0 $. Then the value of $ 2 \cdot \frac{(y(e))^2}{y(e^2)} $ is ________.
Hydrocarbons can be described as organic compounds that consists only hydrogen and carbon atoms. These compounds are of different types and thereby have distinct natures. Hydrocarbons are colorless gases and are known for discharging faint odours. These have been categorized under four major classes named as alkynes, alkanes, alkenes, and aromatic hydrocarbons.