Identify $$\mathrm{N}$$ and $$\mathrm{C}$$ terminal of $$\alpha $$-amino acid respectively in following polypeptide fragment. Ala-Gly-Ser-Tyr-Gly

Which from following formulae is a correct formula to determine percent atom economy?

What is IUPAC name of following compound?

Identify reductant in following reaction.

$$\mathrm{H}_2 \mathrm{~S}+\mathrm{NO}_2 \rightarrow \mathrm{H}_2 \mathrm{O}+\mathrm{NO}+\mathrm{S}$$