What are the positions of ' N ' atoms present in pyrimidine ring of nucleic acids?

Identify the major product obtained when anisole reacts with bromine in acetic acid.

Calculate the molality of nonvolatile solution if solution freezes at $-0.95^{\circ} \mathrm{C}$

$\left[K_f\right.$ for water, $=1.86 \mathrm{~K} \mathrm{~mol}^{-1}$, freezing point of water $=0^{\circ} \mathrm{C}$ ]

Which from following is the most stable species?