Which among the above compound/s does/do not form Silver mirror when treated with Tollen's reagent?

For above chemical reactions, identify the correct statement from the following :

The number of lone pairs of electrons on the central I atom in I$$_3^ - $$ is ____________.

250 mL of 0.5 M NaOH was added to 500 mL of 1 M HCl. The number of unreacted HCl molecules in the solution after complete reaction is ___________ $$\times$$ 10²¹. (Nearest integer)

(N_A = 6.022 $$\times$$ 10²³)