IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry - to identify which is strongest base and acid in given question

singhshivendra

i m not able 2 understand how can we identify strongest acid or base .

viswanath

a strong acid or base completely dissociates into its ions.
out of given options look into the compound that has got the highest tendency to give H+ or OH- ions
i dont think there is any single rule that applies to all compunds

arun-rashi

compound which easily gives H+in solutions are good acid .acidic nature of any compound always increases by -I effect,-R effect because these are electron attracting group so increases acidic nature.for example trichloroacitic acid is more acidic than dichloroacitic acid ,similarly formic acid is more acidic than acitic acid.as the -I or -R efect increases acidic nature also increases for ex.HClO4 is more acidic than HClO3.

arun-rashi

STRONG ACID are HClO4,HCl,HBr,HI,HNO3,H2SO4,H3PO4,C6H5SO3H,HClO3,HClO2 etc.weak acid are organic acid like RCOOH,H2CO3,HF,HOX,(COOH)2,phenol,benzoic acid.

arun-rashi

basic srength are increases by +I effect or +Reffect ,as the electron donation increses or -OH donation increses it also increses basic srength of compound for example CH3NH2 is more basic than ClNH2,similarly sec.amine are more basic than primary amine.in any compound if resonance ocurs it decreases basic nature for example aromatic amine are less basic than aliphatic amine.

arun-rashi

S-block elements form strong base only lithium and berilium forms weak base.d block and f-block form weak base.organic amines are weak bases.

achman

indeed the strongest acid is magic acid SbF5-FSO3H

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