Organic Chemistry Basics Result Question 44
44. What is the decreasing order of strength of the bases?
$\mathrm{OH}^{-}, \mathrm{NH}_2^{-}, \mathrm{H}-\mathrm{C} \equiv \mathrm{C}^{-}$and $\mathrm{CH}_3-\mathrm{CH}_2^{-}$
(a) $\mathrm{CH}_3-\mathrm{CH}_2^{-}>\mathrm{NH}_2^{-}>\mathrm{H}-\mathrm{C} \equiv \mathrm{C}^{-}>\mathrm{OH}^{-}$
(b) $\mathrm{H}-\mathrm{C}=\mathrm{C}^{-}>\mathrm{CH}_3-\mathrm{CH}_2^{-}>\mathrm{NH}_2^{-}>\mathrm{OH}^{-}$
(c) $\mathrm{OH}^{-}>\mathrm{NH}_2^{-}>\mathrm{H}-\mathrm{C}=\mathrm{C}^{-}>\mathrm{CH}_3-\mathrm{CH}_2^{-}$
(d) $\mathrm{NH}_2^{-}>\mathrm{H}-\mathrm{C} \equiv \mathrm{C}^{-}>\mathrm{OH}^{-}>\mathrm{CH}_3-\mathrm{CH}_2^{-}$
(1997)
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Answer:
Correct Answer: 44. ( a )
Solution:
$ \mathrm{CH}_3 \mathrm{CH}_2^{-}>\mathrm{NH}_2^{-}>\mathrm{H}-\mathrm{C} \equiv \mathrm{C}^{-}>\mathrm{HO}^{-} $
It is because the order of acid-strength of their conjugate acid is $\mathrm{CH}_3 \mathrm{CH}_3<\mathrm{NH}_3<\mathrm{H}-\mathrm{C} \equiv \mathrm{C}-\mathrm{H}<\mathrm{H}_2 \mathrm{O}$ : Acid strength.
BETA
