Question

Find the valency of each element mentioned in the following substances:
i) Aluminium in $A{l}_2(S{O}_4{)}_3$ ii) Lead in $Pb{O}_2$ iii) Calcium in $CaO$
iv) Nickel in $NiC{O}_3$ v) Barium in $BaS{O}_3$ vi) Iron in $FeC{l}_2$
vii) Iron in $FeC{l}_3$ viii) Gold in $AuC{l}_3$ ix) Cobalt in $Co(N{O}_3{)}_3$
x) Tin in $Sn(S{O}_4{)}_2$

Answer 1

(i) In $(S{O}_4{)}^{2-}$, valency of $S=+6$ and that of $O=-2$ ;

In $A{l}_2(S{O}_4{)}_3$, valency of $Al=+3$ .

(ii) In $Pb{O}_2$, valency of $Pb=+4$ and that of $O=-2$ .

(iii) In $CaO$, valency of $O=-2$, hence valency of $Ca=+2$ .

(iv) In $NiC{O}_3$, by charge balance, valency of $Ni=+2$ ;

In $(C{O}_3{)}^{2-}$, valency of $C=+4$ and that of $O=-2$ .

(v) In $BaS{O}_3$, there is $(S{O}_3{)}^{2-}$ ion, hence valency of $Ba=+2$ ;

In $(S{O}_3{)}^{2-}$, valency of $S=+4$ and that of $O=-2$ .

(vi) In $FeC{l}_2$, there are $2C{l}^{-}$ ions, hence valency of $Fe=+2$, valency of $Cl=-1$ .

(vii) $FeC{l}_3$ has $3C{l}^{-}$ ions, valency of $Fe=+3$ and that of $Cl=-1$ .

(viii) $AuC{l}_3$ has $3C{l}^{-}$ ions, hence valency of $Au=+3$ and that of $C{l}^{-1}$ .

(ix) $Co(N{O}_3{)}_3$ has $3(N{O}_3{)}^{-}$ ions, hence valency of $Co=+3$;

In $(N{O}_3{)}^{-}$, valency of $N=+5$ and that of $O=-2$ .

(x) $Sn(S{O}_4{)}_2$ has $2(S{O}_4{)}^{2-}$ ions, hence valency of $Sn=+4$ ;

In $(S{O}_4{)}^{2-}$, valency of $S=+6$ and that of $O=-2$ .