Chemistry Class-11: Chapter – 12. The Organic Chemistry Some Basic Principles and Techniques Part – 8 (For CBSE, ICSE, IAS, NET, NRA 2023)
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Question: 48
By mistake, an alcohol (boiling point ) was mixed with a hydrocarbon (boiling point ) . Suggest a suitable method to separate the two compounds. Explain the reason for your choice.
Answer:
Simple distillation can be used because the two compounds have a difference of more than in their boiling points and both the liquids can be distilled without any decomposition.
Question: 49
Which of the two structures (A) and (B) given below is more stabilized by resonance? Explain.
Answer:
Resonating structures are as follows:
(A)
(B)
Structure ‘B’ is more stabilized as it does not involve charge separation.
IV. Matching Type
In the following questions more than one correlation is possible between options of Column I and Column II. Make as many correlations as you can.
Question: 50
Match the type of mixture of compounds in Column I with the technique of separation/purification given in Column II.
| Column I | Column I | ||
| (i) | Two solids which have different solubility՚s in a solvent and which do not undergo reaction when dissolved in it. | a | Steam distillation |
| (ii) | Liquid that decomposes at its boiling point | b | Fractional distillation |
| (iii) | Steam volatile liquid | c | Simple distillation |
| (iv) | Two liquids which have boiling points close to each other | d | Distillation under reduced pressure |
| (v) | Two liquids with large difference in boiling points | e | Crystallization |
Answer:
(i) ⇾ (e) (ii) ⇾ (d) (iii) ⇾ (a) (iv) ⇾ (b) (v) ⇾ (c)
Question: 51
Match the terms mentioned in Column I with the terms in Column II.
| Column I | Column I | ||
| (i) | Carbocation | a | Cyclohexane and 1- hexane |
| (ii) | Nucleophile | b | Conjugation of electrons of bond with empty p-orbital present at adjacent positively charged carbon. |
| (iii) | Hyperconjugation | c | hybridised carbon with empty p-orbital |
| (iv) | Isomers | d | Ethyne |
| (v) | hybridisation | e | Species that can receive a pair of electrons |
| (vi) | Electrophile | Species that can supply a pair of electrons | |
Answer:
(i) ⇾ (c) (ii) ⇾ (f) (iii) ⇾ (b) (iv) ⇾ (a) (v) ⇾ (d) (vi) ⇾ (e)
Question: 52
Match Column I with Column II.
| Column I | Column I | ||
| (i) | Duma՚s method | a | |
| (ii) | Kjeldahl method | b | Silica gel |
| (iii) | Carious method | c | Nitrogen gas |
| (iv) | Chromatography | d | Free radicals |
| (v) | Hemolysis | e | Ammonium sulphate |
Answer:
(i) ⇾ (c) (ii) ⇾ (e) (iii) ⇾ (a) (iv) ⇾ (b) (v) ⇾ (d)
Question: 53
Match the intermediates given in Column I with their probable structure in Column II.
| Column I | Column I | ||
| (i) | Free radical | a | Trigonal planar |
| (ii) | Carbocation | b | Pyramidal |
| (iii) | Carbanion | c | Linear |
Answer:
(i) ⇾ (a) , (ii) ⇾ (a) (iii) ⇾ (b)
Question: 54
| Column I | Column I | ||
| (i) |  | a | |
| (ii) | b | Stable due to resonance | |
| (iii) | c | Destabilized due to inductive effect | |
| (iv) | Stabilized by hyperconjugation | d | A secondary carbocation |
Answer:
(i) ⇾ (a) , (b) , (d) (ii) ⇾ (b) (iii) ⇾ (b) (iv) ⇾ (c) , (d)