MCQOPTIONS
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MCQOPTIONS
This section includes 17 Mcqs, each offering curated multiple-choice questions to sharpen your Organic Chemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
What is the specific optical rotation of (S)-malic acid at a concentration of 5.5 g/ mL in the solvent pyridine at 20°C at a wavelength of 589 nm? |
| A. | the specific rotation is –27° |
| B. | the specific rotation is +27° |
| C. | the specific rotation is –17° |
| D. | the specific rotation is +17° |
| Answer» B. the specific rotation is +27° | |
| 2. |
Which of these is a comparatively insignificant factor affecting the magnitude of specific optical rotation? |
| A. | Concentration of the substance of interest |
| B. | Purity of the sample |
| C. | Temperature of the measurement |
| D. | Length of the sample tube |
| Answer» D. Length of the sample tube | |
| 3. |
What can be said with certainty if a compound has α= -9.25°? |
| A. | The compound has the (S) configuration |
| B. | The compound has the (R) configuration |
| C. | The compound is not a meso form |
| D. | The compound possesses only one stereogenic center |
| Answer» D. The compound possesses only one stereogenic center | |
| 4. |
What is the percent composition of a mixture of (S)-(+)-2-butanol, α= +13.52°, and (R)-(-)-2-butanol, α = -13.52°, with a specific rotation α = +6.76°? |
| A. | 75%(R) 25%(S) |
| B. | 25%(R) 75%(S) |
| C. | 50%(R) 50%(S) |
| D. | 67%(R) 33%(S) |
| Answer» C. 50%(R) 50%(S) | |
| 5. |
If a solution of a compound (30.0 g/100 mL of solution) has a measured rotation of +15° in a 2 dm tube, what is the specific rotation? |
| A. | +50° |
| B. | +25° |
| C. | +15° |
| D. | +7.5° |
| Answer» C. +15° | |
| 6. |
What is the effect of the I on the specific optical rotation (α), if I gets double? |
| A. | α gets double |
| B. | α gets halved |
| C. | α gets four times |
| D. | α eight times |
| Answer» B. α gets halved | |
| 7. |
A solution of 0.1 g/mL of a pure R enantiomer in a 1.0 dm (i.e., 10 cm) polarimeter rotates plane polarized light by +4.8°. What is the rotation observed on this solution in a 2 dm polarimeter? |
| A. | +2.4° |
| B. | +4.8° |
| C. | +19° |
| D. | +9.6° |
| Answer» E. | |
| 8. |
WHICH_OF_THESE_IS_A_COMPARATIVELY_INSIGNIFICANT_FACTOR_AFFECTING_THE_MAGNITUDE_OF_SPECIFIC_OPTICAL_ROTATION??$ |
| A. | Concentration of the substance of interest |
| B. | Purity of the sample |
| C. | Temperature of the measurement |
| D. | Length of the sample tube |
| Answer» D. Length of the sample tube | |
| 9. |
What_is_the_specific_optical_rotation_of_(S)-malic_acid_at_a_concentration_of_5.5_g/_mL_in_the_solvent_pyridine_at_20°C_at_a_wavelength_of_589_nm?$# |
| A. | the specific rotation is –27° |
| B. | the specific rotation is +27° |
| C. | the specific rotation is –17° |
| D. | the specific rotation is +17° |
| Answer» B. the specific rotation is +27¬¨¬®‚Äö√†√ª | |
| 10. |
What can be said with certainty if a compound has α= -9.25°?# |
| A. | The compound has the (S) configuration |
| B. | The compound has the (R) configuration |
| C. | The compound is not a meso form |
| D. | The compound possesses only one stereogenic center |
| Answer» D. The compound possesses only one stereogenic center | |
| 11. |
What is the percent composition of a mixture of (S)-(+)-2-butanol, α= +13.52°, and (R)-(-)-2-butanol, α = -13.52°, with a specific rotation α = +6.76°?$ |
| A. | 75%(R) 25%(S) |
| B. | 25%(R) 75%(S) |
| C. | 50%(R) 50%(S) |
| D. | 67%(R) 33%(S) |
| Answer» C. 50%(R) 50%(S) | |
| 12. |
Which of the following groups has the highest priority according to the Cahn-Ingold-Prelog sequence rules? |
| A. | CH<sub>3</sub> |
| B. | CH<sub>2</sub>Cl |
| C. | CH<sub>2</sub>OH |
| D. | CHO |
| Answer» C. CH<sub>2</sub>OH | |
| 13. |
If a solution of a compound (30.0 g/100 mL of solution) has a measured rotation of +15° in a 2 dm tube, what is the specific rotation?$ |
| A. | +50° |
| B. | +25° |
| C. | +15° |
| D. | +7.5° |
| Answer» C. +15¬¨¬®‚Äö√†√ª | |
| 14. |
What is the effect of the I on the specific optical rotation (α), if I gets double?$ |
| A. | α gets double |
| B. | α gets halved |
| C. | α gets four times |
| D. | α eight times |
| Answer» B. ‚âà√≠¬¨¬± gets halved | |
| 15. |
Polarimeter works on the principle of which of the following? |
| A. | polarisation of light |
| B. | change of the electrical conductivity of solution with composition |
| C. | change of angle of refraction with composition |
| D. | change of electrical conductivity of solution with temperature |
| Answer» B. change of the electrical conductivity of solution with composition | |
| 16. |
A solution of 0.1 g/mL of a pure R enantiomer in a 1.0 dm (i.e., 10 cm) polarimeter rotates plane polarized light by +4.8°. What is the rotation observed on this solution in a 2 dm polarimeter?$ |
| A. | +2.4° |
| B. | +4.8° |
| C. | +19° |
| D. | +9.6° |
| Answer» E. | |
| 17. |
What does a polarimeter measure? |
| A. | Polarity of the substance |
| B. | Angle of rotation of an optical active compound |
| C. | Concentration of the substance |
| D. | pH of the substance |
| Answer» C. Concentration of the substance | |