Identify the reagent ' R ' used in the following reaction. Benzoyl chloride $$ \to $$ Benzaldehyde

What is the representation of an element having mass number of 40 and 21 neutrons in it?

How many moles of dioxygen are present in $8.314 \times 10^{-3} \mathrm{~m}^3$ of it at 318 K having pressure $3.18 \times 10^5 \mathrm{Nm}^{-2} ?\left(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$

Which of the following compounds has difficulty in breaking the $\mathrm{C}-\mathrm{Cl}$ bond?