question_answer 1)

Calculate the oxidation number of sulphur, chromium and nitrogen in \[{{H}_{2}}S{{O}_{5}},C{{r}_{2}}O_{7}^{2-}\] and\[NO_{3}^{-}\]. Suggest structure of these compounds. Count for the fallacy.  

Answer:

(i)\[\overset{+1}{\mathop{H}}\,-\overset{-2}{\mathop{O}}\,-\underset{\underset{\underset{-2}{\mathop{O}}\,}{\mathop{||}}\,}{\overset{\overset{\overset{-2}{\mathop{O}}\,}{\mathop{||}}\,}{\mathop{S}}}\,-\overset{-1}{\mathop{O}}\,-\overset{-1}{\mathop{O}}\,-\overset{+1}{\mathop{H}}\,\] \[x+2-8=0\] \[x=+6\] Here, x is the oxidation state of sulphur. (ii) \[\overset{-}{\mathop{O}}\,-\underset{\underset{O}{\mathop{||}}\,}{\overset{\overset{O}{\mathop{||}}\,}{\mathop{Cr}}}\,-O-\underset{\underset{O}{\mathop{||}}\,}{\overset{\overset{O}{\mathop{||}}\,}{\mathop{Cr}}}\,-\overset{-}{\mathop{O}}\,\] Let x be the oxidation state of chromium. \[\therefore \] \[2x-14=-2\] \[x=+6\] (iii) Let oxidation state of nitrogen is \[x-6=1\] \[x=+5\]