General Series - Chemistry Fact Sheet

General Series - Chemistry Fact Sheet - 3

General series	Order	Why ?
1.		I > II > III	There is intermolecular H-bonding I. III has weak force of attraction and is most volatile.
2.	*B.P. of o, m, p-nitro phenol*	o < m < p	Intramolecular H-bonding in o-isomer makes it more volatile.
3.	Reactivity of … with Tollen’s reagent	I > II > IV > III	—CHO group is easily oxidised compared to keto group due to redusing hydrogen.
4.	Reactivity of … with Fehling’s solution	I > II > IV > III	—do—
5.	Extent of hydration of	I < II < III < IV	Aldehydes are more hydrated than ketones. Halide makes C of carbonyl group more electropositive.
6.	Electrophilic nature of …….. for nucleophilic attack	I > II > III	CH₃ group decreases +ve charge on C hence nucleophilic attack.
7.	Reactivity of isomeric 1°, 2°, 3° butyl halide towards elimination (E1 or E2)	3° < 2° < 1°	due to stability of intermediate carbocation
8.	Dehydration of	IV < I < II < III	Alcohol leading to increase in conjugation due to dehydration is more easily dehydration is more easily dehydrated. IV is vinylic, hence least.
9.	Stability of
		I < II < III < IV < V < VI	Substituted alkenes are more stable.More the alkyl groups are attached to the doubly bonded carbon atom more is the stability.
10.	Stability of	I < III < II	II is more substituted than III (More hyperconjugation more stability)
11.	Stability of	III > II > I > IV	IV is vinylic while in conjugative, II allylic.
12.	Stability of	I < IV < II < III	III is 3° allylic and II is 1° allylic
13.	Dehydration of 1°, 2°, 3° isomeric butyl alcohol	3° < 2° < 1°	More the stability of intermediate, greater the reactivity of chemical reaction.
14.	Boiling points of	II > I > III	I, II have H-bonding but electronegativity of O > N hence H-bonding in II > I
15.	Formation of	I > II > III > IV (easiest I)	greater the stability, easier the formation of perticular species.
16.	Reactivity of C—H bond (abstraction of H)
		I < II < III < IV < V < VI	Vinyl < methyl 1° < 2° < 3° < allylic
17.	Leaving nature (tendency) of … in S_N reaction.	I < II < III ~ IV < V < VI < VII < VIII	If acid is strong, its conjugate base is weak and greater the leaving tendency.
18.	Rate of esterification of the following acids with MeOH	I > II > III > IV > V	As the size of the substituents on the —C increases, the tetrahedrally bonded interme. diate becomes more crowded and these slower the rate.
19.	Relative reactivity of … with electrophile in S_E reaction
		I > II > IV > III > V	—CH₃ is o-, p-directing and responsible for activation.
20.	Relative reactivity of these compunds with electrophile inS_E reaction	II > I > III > IV	—CH₃ is o-, p-directing due to activation while —COOH is m-directing and deactivating group.
21.	Relative reactivity of … with electrophile in S_E reaction.	II > I > IV > II	As the number of sp³ hybridised C atoms separating the ring from the positively charged substituent increases, deactivating effect decreases due to less electronegativity.
22.	Activating effects of the following o, p-directors.	II > I > III	is best able to donate electrons there by giving a very stable uncharged intermediate. In cross conjugation diminished its ability to donate electrons to an arenium ion.
23.	Relative reactivity of … towards S_N1 reaction	II > I > III	Intermediates are benzylic cations. So CH₃O(electron repelling) gives greater stability through delocalisation while NO₂ (electron attracting) decreases stability.
24.	Relative reactivity of … towards S_N1 and S_N2 reaction	S_N1 : III > II > I S_N2 : II < II < I	S_N1 : 1° < 2° < 3° alkyl halide S_N2 : 3° < 2° < 1° alkyl halide
25.	Relative reactivity of … with E⁺ (electrophile) in S_E reaction.	II > I > III	—NO₂ deactivates benzene ring for S_E

26.	Order of S_N2 reactivity of alkoxide nucleophiles
		I < IV < V < III < II	S_N2 reactivity is suseptible to steric hindrance by the nucleophile as well as by the size of alkyl group.

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