Explain how does the –OH group attached to a carbon of benzene ring activate it towards electrophilic substitution?
The -OH group is an electron-donating group. Thus, it increases the electron density in the benzene ring as shown in the given resonance structure of phenol. As a result, the benzene ring is activated towards electrophilic substitution.


A racing track is built around an elliptical ground whose equation is given by \[ 9x^2 + 16y^2 = 144 \] The width of the track is \(3\) m as shown. Based on the given information answer the following: 
(i) Express \(y\) as a function of \(x\) from the given equation of ellipse.
(ii) Integrate the function obtained in (i) with respect to \(x\).
(iii)(a) Find the area of the region enclosed within the elliptical ground excluding the track using integration.
OR
(iii)(b) Write the coordinates of the points \(P\) and \(Q\) where the outer edge of the track cuts \(x\)-axis and \(y\)-axis in first quadrant and find the area of triangle formed by points \(P,O,Q\).
Alcohols, phenols, and ethers are organic compounds that can be classified based on their molecular structure and functional groups.
Classification of Alcohols:
Classification of Phenols:
Classification of Ethers:
In summary, alcohols, phenols, and ethers can be classified based on their molecular structure and functional groups. Understanding the classification of these compounds is important for predicting their reactivity and understanding their potential applications in various fields, including chemistry, biology, and industry.