Two moles of an ideal gas are compressed isothermally and reversibly from 40 L to 20 L at 300 K . What is the work done? $\left(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$

Identify the product ' $A$ ' obtained in following reaction.

N -alkyl phthalimide $\xrightarrow{\mathrm{N}_2 \mathrm{OH}_{(a q)}}$ sodium phthalate + A

Which among the following is the conjugate base of $\mathrm{HClO}_4$ ?

Which from following polymers contain - CO - NH - linkage in it?