2.5 mL of $$\frac{2}{5}$$M weak monoacidic base (K$$_b$$ = 1 $$\times$$ 10$$^{-12}$$ at 25$$^\circ$$C) is titrated with $$\frac{2}{15}$$M HCl in water at 25$$^\circ$$C. The concentration of H$$^+$$ at equivalence point is (K$$_w$$ = 1 $$\times$$ 10$$^{-14}$$ at 25$$^\circ$$C).

The correct statement(s) about the compound given below is(are):

The correct statement(s) concerning the structures E, F and G is(are) :

A solution of colourless salt H on boiling with excess NaOH produces a non-flammable gas. The gas evolution ceases after sometime. Upon addition of Zn dust to the same solution, the gas evolution restarts. The colourless salt(s) H is(are):