The conjugate base of $NH_{3}$ is

The conjugate base of phosphorus acid is $x$. The conjugate base of oleum is $y$. What are $x$ and $y$,respectively?

The conjugate acid of $NH_2^-$ is

Classify the following species into Lewis acids and Lewis bases and show how these act as Lewis acid/base:
$(a) OH^{-}$
$(b) F^{-}$
$(c) H^{+}$
$(d) BCl_{3}$

Which of the following fertilizers increases the acidity of the soil upon regular use?

$NH_3$ gas dissolves in water to give $NH_4OH$. In this reaction,water acts as a/an ...... .