Identify base$$_2$$ for following equation according to Bronsted-Lowry theory.

$$\mathrm{HCl}_{(\mathrm{aq})}+\mathrm{H}_2 \mathrm{O}_{(l)} \rightleftharpoons \mathrm{H}_3 \mathrm{O}_{(\mathrm{aq})}^{+}+\mathrm{Cl}_{(\mathrm{aq})}^{-}$$

Which of the following is Clemmensen reduction?

Which of the following gases is readily adsorbed by solid adsorbent?

Which from following is an example of two dimensional nanostructures?