50
Subjective
Match the type of mixture of compounds in Column I with the technique of separation/purification given in column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Two solids which have different solubilities in a solvent and which do not undergo reaction when dissolved in it | 1. | Steam distillation |
| B. | Liquid that decomposes at its boiling point | 2. | Fractional distillation |
| C. | Steam volatile liquid | 3. | Simple distillation |
| D. | Two liquids which have boiling points close to each other | 4. | Distillation under reduced pressure |
| E. | Two liquids with large difference in boiling points. | 5. | Crystallisation |
Explanation
A - (5), B - (4), C - (1), D - (2), E - (3)
| Column I | Column II | ||
|---|---|---|---|
| A. | Two solids which have different solubilities in a solvent and which do not undergo reaction when dissolved in it | 1. | Crystallisation |
| B. | Liquid that decomposes at its boiling point | 2. | Distillation under reduced pressure |
| C. | Steam volatile liquid | 3. | Steam distillation |
| D. | Two liquids which have boiling points close to each other | 4. | Fractional distillation |
| E. | Two liquids with large difference in boiling points. | 5. | Simple distillation |
51
Subjective
Match the terms mentioned in Column I with the terms in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Carbocation | 1. | Cyclohexane and 1-hexene |
| B. | Nucleophile | 2. | Conjugation of electrons of C-H$$\sigma$$ bond with empty p-orbital present at adjacent positively charged carbon |
| C. | Hyperconjugation | 3. | sp$$^2$$ hybridised carbon with empty p-orbital |
| D. | Isomers | 4. | Ethyne |
| E. | sp-hybridisatioin | 5. | Species that can receive a pair of electrons |
| F. | Electrophile | 6. | Species that can supply a pair of electrons |
Explanation
A - 3, B - 6, C - 2, D - 1, E - 4, F - 5
| Column I | Column II | Explanation | |
|---|---|---|---|
| A. | Carbocation | sp$$^2$$-hybridised carbon with empty p-orbital | H$$_3$$C$$^+$$ is carbocation. Loss of e$$^-$$ makes its p-orbitals empty (sp$$^2$$-hybridised carbon) |
| B. | Nucleophile | Species that can supply a pair of electron | Nucleus loving i.e., having negative charge or excess of electrons |
| C. | Hyperconjugation | Conjugation of electrons of $\mathrm{C}-\mathrm{H} \sigma$ bond with empty $p$-orbital present at adjacent positively charged carbon | |
| D. | Isomers | Cyclohexane and 1-hexene | Same molecular formula but different structures |
| E. | sp-hybridisatioin | Ethyne | HC = CH (sp-hybridisation) |
| F. | Electrophile | Species that receive a pair of electron | Electron loving i.e., positive charge or lack of electrons |
52
Subjective
Match column I with column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Dumas method | 1. | AgNO$$_3$$ |
| B. | Kjeldahl's method | 2. | Silica gel |
| C. | Carius method | 3. | Nitrogen gel |
| D. | Chromatography | 4. | Free radicals |
| E. | Homolysis | 5. | Ammonium sulphate |
Explanation
A - 3, B - 5, C - 1, D - 2, E - 4
| Column I | Column II | Explanation | |
|---|---|---|---|
| A. | Dumas method | Nitrogen gel | Used for N containing compounds |
| B. | Kjeldahl's method | Ammonium sulphate | Nitrogen converts to ammonium sulphate |
| C. | Carius method | AgNO$$_3$$ | Compound is heated in presence of AgNO$$_3$$ |
| D. | Chromatography | Silica gel | Adsorbent used is silica gel |
| E. | Homolysis | Free radical | Free radicals are formed by homolytic fission |
53
Subjective
Match the intermediates given in Column I with their probable structure in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Free radical | 1. | Trigonal planar |
| B. | Carbocation | 2. | Pyramidal |
| C. | Carbanion | 3. | Linear |
Explanation
A - 1, B - 1, C - 2
| Column I | Column II | Explanation | |
|---|---|---|---|
| A. | Free radical | Trigonal planar | Free radicals are formed by homolytic fission e.g... ${ }^{\Upsilon} \mathrm{H}_3$ hybridisation $s p^2$ |
| B. | Carbocation | Trigonal planar | Formed by heterolytic fission when carbon is attached to a more electronegative atom |
| C. | Carcanion | Pyramidal | Formed by heterolytic fission when carbon is attached to more electropositive atom e.g.. $\mathrm{CH}_3^{-}$hybridisation $\mathrm{sp}^3$ |
54
Subjective
Match the ions given in Column I with their nature given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. |  |
1. | Stable due to resonance |
| B. | $\mathrm{F}_3-\mathrm{C}^{\oplus}$ | 2. | Destablised due to inductive effect |
| C. |  |
3. | Stabilised by hyperconjugation |
| D. | $\mathrm{CH}_3-\stackrel{\oplus}{\mathrm{C}} \mathrm{H}-\mathrm{CH}_3$ | 4. | A secondary carbocation |
Explanation
A - (1, 2), B - (2), C - (2), D - (3, 4)
| Column I | Column II | Explanation | |
|---|---|---|---|
| A. |  |
Stable due to resonance Destabilised due to inductive effect |
|
| B. | $\mathrm{F}_3-\mathrm{C}^{+}$ | Destabilised due to inductive effect | $$-I$$ effect of F creates electron deficiency at carbon $\mathrm{C}^{+}$ |
| C. |  |
Destablised due to inductive effect | + l effect of $\mathrm{CH}_3$ increases electron density at carbon $\mathrm{C}^{-}$ |
| D. | $\mathrm{CH}_3-\stackrel{\oplus}{\mathrm{C}} \mathrm{H}-\mathrm{CH}_3$ | A secondary carbocation stabilised due to hyperconjugation | $\stackrel{+}{\mathrm{C}} \mathrm{H}$ is attached to two carbon. It can also be stabilised by hyperconjugation. |