Write structure of the products of the following reactions: 
(a) Anisole (methoxybenzene) reacts with HI.
HI protonates the ether oxygen and breaks the C–O bond.
The methyl group leaves as methyl iodide (CH$_3$I) and phenol (C$_6$H$_5$OH) is formed.
So, products are: Phenol + CH$_3$I.
(b) Phenol activates the benzene ring strongly towards electrophilic substitution.
With concentrated nitric acid, multiple nitro groups attach to ortho and para positions.
So, 2,4,6-trinitrophenol (picric acid) is formed.
This reaction is an example of nitration of an activated aromatic compound.
(c)The Grignard reagent (Cyclohexyl–MgBr) attacks the carbonyl carbon of formaldehyde.
This forms an alkoxide intermediate.
On acid hydrolysis, the alkoxide is protonated to give a primary alcohol.
So, the product is cyclohexylmethanol (Cyclohexane–CH$_2$–OH).
Convert Ethanal to But-2-enal

A ladder of fixed length \( h \) is to be placed along the wall such that it is free to move along the height of the wall.
Based upon the above information, answer the following questions:
(iii) (b) If the foot of the ladder, whose length is 5 m, is being pulled towards the wall such that the rate of decrease of distance \( y \) is \( 2 \, \text{m/s} \), then at what rate is the height on the wall \( x \) increasing when the foot of the ladder is 3 m away from the wall?