$$BC{l_3},\,\,H = \frac{1}{2}\left( {3 + 3 + 0 - 0} \right) = 3;\,s{p^2}\,{\text{hybridization}}$$
$$\left( {{\text{bond}}\,{\text{angle}} = {{120}^ \circ }} \right)$$ similarly $$PC{l_3}\,AsC{l_3}$$ and $$BiC{l_3}$$ are found to have $$s{p^3}$$ hybridized central atom with one lone pair of electrons on the central atom. The bond angle \[\le {{109}^{\circ }}28',\] since the central atoms belong to the same group, the bond angle of the chlorides decreases as we go down the group. Thus the order of bond angle is, $$BC{l_3} > PC{l_3} > AsC{l_3} > BiC{l_3}.\,$$
572.
Identify $$X$$ and $$Y$$ in the following reaction : \[BC{{l}_{3}}+N{{H}_{4}}Cl\xrightarrow[{{C}_{6}}{{H}_{5}}Cl]{{{140}^{\circ }}C}X\] \[\xrightarrow{NaB{{H}_{4}}}Y\]
Electron affinity decreases down the group as atomic size increases.
576.
The following acids have been arranged in order of decreasing acid strength. Identify the correct order.
$$\eqalign{
& \left( {\text{i}} \right)ClOH \cr
& \left( {{\text{ii}}} \right)BrOH \cr
& \left( {{\text{iii}}} \right)IOH \cr} $$
The tendency to show + 2 oxidation state increases down the group. It is due to inability of $$n{s^2}$$ electrons of valence shell to participate in bonding.
579.
In qualitative analysis when $${H_2}S$$ is passed through an aqueous solution of salt acidified with \[dil.HCl,\] a black precipitate is obtained. On boiling the precipitate with \[dil.HN{{O}_{3}},\] it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives _________.
A
deep blue precipitate of $$Cu{\left( {OH} \right)_2}$$
B
deep blue solution of $${\left[ {Cu{{\left( {N{H_3}} \right)}_4}} \right]^{2 + }}$$
C
deep blue solution of $$Cu{\left( {N{O_3}} \right)_2}$$
D
deep blue solution of $$Cu{\left( {OH} \right)_2} \cdot Cu{\left( {N{O_3}} \right)_2}$$
Answer :
deep blue solution of $${\left[ {Cu{{\left( {N{H_3}} \right)}_4}} \right]^{2 + }}$$