Question practice on acidic nature:
Q.1; following organic compounds ko acidic nature me arrange kijiye:
B..C2H5OH
C..CH2=CH2
D..CH3-OH
ANS: C<B<A<D
REASON: acidic nature Pka value parr birbhar karta hai, jitna kam Pka value hoga utna jyaada compound ki acidic nature hoga.
Ethene ka Pka value 44 above questions me sabse jyaada,Ethanol ki Pka value 15.9, water kii Pka value 15.7 and methanol kiii Pka value lagbhag 15.5 hota hai jo ki water se kamm hai,isliye water se adhik acidic hai.
Ethene se jyaada acidic acetylene hota hai kyoki ethene me percentage of S character SP2 hybridisation k kaaran 33.3 ke aaspas hota hai and acetylene ki hybridisation SP hotii hai jisse percentage of S character very high hoti hai(50%). Acetylene ki Pka value 25 hoti hai.
+I effect acidic nature ko kamm karta hai tathaa -i effect acidic nature ko increase karta hai.
Ethanol me CH3CH2 GP +I effect ke kaaran oxygen parr electron density ko increase kar detaa hai jisse proton freee mushkil se hota hai isliye kamm acid hai.
water me naa hiii +i effect aur naa hii -i effect paya jaata hai isliye water, Ethanol, acetylene aur ethene se bhi jyaada acidic hai.
Experimentally methanol ki acidic nature water se bhi jyaada hotii hai,aisa Pka value se pta chalta hai jo ki experimental data hai.
Question.2:
Acidic character k increasing order me arrange kijiye:
A..HCOOH
B..CH3COOH
C..benjoic acid
D..Chloro ethanoic acidic
E..Iodo propanoic acid
ANS:
B<C<A<E<D
Formic acid ki pka value 3.75, acetic acid ki pka value 4.75, benjoic acid ki pka value 4.20, chloro acetic acid ki pka value 2.87 and iodo propanoic acid ki pka value lagbhag 3 k aaspass hotii hai.
CH3COOH mein CH3 group acidic nature ko decrease karta hai.
HCOOH mein inductive effect nahii hone ke kaaran inki acidic nature ethanol and benjoic se adhik hotii hai.
Benjoic acid me resonance paya jataa hai.
Chloro acetic acid ki pka value above questions me se sabse kammm hoti hai,isliye acidic nature adhikk hotii hai.
Question.3
Acidic nature me arrange kijiye:
A..tri fluoro methane sulphonic acid
B.. Benzene sulphonic acid
C..methane sulphonic acid
D..tri fluoro acetic acid
ANS:
D<C<B<A
Sulphonic acid sabse jyaada acidic hotaa hai.
Q.4
Acidic nature me arrange kijiye:
A..Floro acetic acid
B..Chloro acetic acid
C..Iodo acetic acid
D..Bromo acetic acid
E.. acetic acid
ANS:
E<C<D<B<A
aisa isliye hota hai kyoki Fluorine sabse jyaada electronegativity element hai.
Electronegativity order...I<Br<Cl<F
Concept
Lewis's conjugate acid base theory ke anusaar jo best acid hotaa hai vo weakest base hotaa hai.
So upar diye gye sabhi questions ko aaap basic order me bhi banane ki koshish kijiye...basic order, acid order ke just opposite hota hai.
For example
Question... Basic order me arrange kijiye:
A..HCOOH
B..CH3COOH
C..benjoic acid
D..Chloro ethanoic acidic
E..Iodo propanoic acid
ACIDIC ORDER= B<C<A<E<D
BASIC ORDER=D<E<A<C<B
Thanks readers🙏🙏..keep reading...aur bhi acche acche acidic nature pe question karenge uske pahle padhenge Resonance...padhte rahiye and take care🤗
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