For first order reaction the concentration of reactant decreases from 0.2 to 0.1 M in 100 minutes. What is the rate constant of the reaction?

The end product $C$ of the following reaction is

$$\mathrm{C}_2 \mathrm{H}_5 \mathrm{NH}_2 \xrightarrow{\mathrm{HNO}_2} A \xrightarrow{\mathrm{PCl}_5} B \xrightarrow[\text { Alcohol }]{\mathrm{NH}_3} C$$

Which among the following sets of elements is present in chalcopyrite?

Which of the following pairs of monomers is used for the preparation of dextron?