A) \[{{\operatorname{F}}^{-}}<{{\operatorname{CN}}^{-}}<\operatorname{NO}_{2}^{-}\]
B) \[NO_{2}^{-}<C{{N}^{-}}<{{F}^{-}}\]
C) \[{{\operatorname{F}}^{-}}<\operatorname{NO}_{2}^{-}<{{\operatorname{CN}}^{-}}\]
D) \[\operatorname{NO}_{2}^{-}<\operatorname{F}_{{}}^{-}<\operatorname{CN}_{{}}^{-}\]
Correct Answer: C
Solution :
Higher the value of \[{{K}_{a}}\]lower will be the value of \[p{{K}_{a}}\]i.e. higher will be the acidic nature. Furth since \[\text{CN}_{,}^{-}{{\text{F}}^{-}}\]and \[\text{N}{{\text{O}}_{\text{2}}}^{-}\]are conjugate base of the acids HCN, HF and \[\text{HN}{{\text{O}}_{\text{2}}}\]respectively hence the correct order of base strength will be \[{{F}^{-}}<N{{O}_{2}}^{-}<C{{N}^{-}}\] (stronger the acid weaker will be its conjugate base)You need to login to perform this action.
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