Which of the following molecular hydrides acts as a Lewis acid?

1. $N{H}_3$

2. $H_{2}O$

3. $B_2{H}_6$

4. $C{H}_4$

The tendency of BF₃, BCl₃ and BBr₃ to behave as Lewis acid decreases in the sequence:

1. $BC{l}_3>B{F}_3>BB{r}_3$

2. $BB{r}_3>BC{l}_3>B{F}_3$

3. $BB{r}_3>B{F}_3>BC{l}_3$

4. $B{F}_3>BC{l}_3>BB{r}_3$

The ionic species that has the greatest proton affinity to form stable compound is:

1. $H{S}^{-}$

2. $N{H}_2^{-}$

3. $F^{-}$

4. $l^{-}$

Which one of the following orders correctly represents the increasing acid strengths of the given acids?

1. $HOCl<HOClO<HOCl{O}_2<HOCl{O}_3$

2. $HOClO<HOCl<HOCl{O}_3<HOCl{O}_2$

3. $HOCl{O}_2<HOCl{O}_3<HOClO<HOCl$

4. $HOCl{O}_3<HOCl{O}_2<HOClO<HOCl$