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This section includes 15 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. |
The ultraviolet spectrum of benzonitrile shows a secondary absorption band at 271 nm. If a solution of benzonitrile in water, with a concentration of 1×10-4 molar solution is examined at 271 nm, what will be the absorbance reading (ℇ = 1000) and what will be the intensity ratio, IO/I, respectively? |
A. | 0.1, 1.26 |
B. | 0.2, 2.26 |
C. | 0.3, 3.26 |
D. | 0.4, 4.26 |
Answer» B. 0.2, 2.26 | |
2. |
The ultraviolet spectrum of benzonitrile shows a primary absorption band at 224 nm. If a solution of benzonitrile in water, with a concentration of 1x 10-4 molar, is examined at a wavelength of 224 nm, the absorbance is determined to be 1.30. The cell length is 1 cm. What is the molar absorptivity of this absorption band? |
A. | 2.3 x 104 |
B. | 3.3 x 104 |
C. | 1.3 x 104 |
D. | 4.3 x 104 |
Answer» D. 4.3 x 104 | |
3. |
Which of the following is the correct order of λmax for n–> π* transition for the given compounds? |
A. | 1>2>3>4>5 |
B. | 1<2<3<4<5 |
C. | 1>2<3>4<5 |
D. | 1>2>3<4>5 |
Answer» B. 1<2<3<4<5 | |
4. |
What is the correct order of λmax for n–> π* transition for the following three compounds? |
A. | RCOOH > RCOOR’ > RCONH2 |
B. | RCOOH = RCOOR’ = RCONH2 |
C. | RCOOH = RCOOR’ < RCONH2 |
D. | RCOOH = RCOOR’ > RCONH2 |
Answer» C. RCOOH = RCOOR’ < RCONH2 | |
5. |
What is the correct order of λmax for π –> π* transition for the following three compounds? |
A. | R-C=C-R > R2C = CR2 > R-CHO |
B. | R-C=C-R < R2C = CR2 < R-CHO |
C. | R-C=C-R = R2C = CR2 = R-CHO |
D. | R-C=C-R < R2C = CR2 >R-CHO |
Answer» C. R-C=C-R = R2C = CR2 = R-CHO | |
6. |
What is the correct order of λmax for n –> π* transition for the R-CN, R-NO2, and R-N=N-R? |
A. | R-CN < R-NO2 < R-N=N-R |
B. | R-CN = R-NO2 = R-N=N-R |
C. | R-CN > R-NO2 > R-N=N-R |
D. | R-CN > R-NO2 < R-N=N-R |
Answer» B. R-CN = R-NO2 = R-N=N-R | |
7. |
What is the correct order of λmax for n –> σ* transition? |
A. | R-OH > R-NH2 > R-SH |
B. | R-OH < R-NH2 < R-SH |
C. | R-OH > R-SH > R-NH2 |
D. | R-OH < R-SH < R-NH2 |
Answer» C. R-OH > R-SH > R-NH2 | |
8. |
Which of the following comparison is correct for solvent shift on the n –>π* transition of acetone? |
A. | H20 = CH30H = C2H50H = CHC13 = C6H14 |
B. | H20 > CH30H > C2H50H > CHC13 > C6H14 |
C. | H20 < CH30H < C2H50H < CHC13 < C6H14 |
D. | H20 > CH30H < C2H50H < CHC13 < C6H14 |
Answer» D. H20 > CH30H < C2H50H < CHC13 < C6H14 | |
9. |
THE_ULTRAVIOLET_SPECTRUM_OF_BENZONITRILE_SHOWS_A_SECONDARY_ABSORPTION_BAND_AT_271_NM._IF_A_SOLUTION_OF_BENZONITRILE_IN_WATER,_WITH_A_CONCENTRATION_OF_1‚ÄÖ√†√∂‚Àւ•10-4_MOLAR_SOLUTION_IS_EXAMINED_AT_271_NM,_WHAT_WILL_BE_THE_ABSORBANCE_READING_(‚ÄÖ√Ñ√∂‚ÀÖ√´‚ÀÖ¬∞_=_1000)_AND_WHAT_WILL_BE_THE_INTENSITY_RATIO,_IO/I,_RESPECTIVELY??$# |
A. | 0.1, 1.26 |
B. | 0.2, 2.26 |
C. | 0.3, 3.26 |
D. | 0.4, 4.26 |
Answer» B. 0.2, 2.26 | |
10. |
The ultraviolet spectrum of benzonitrile shows a primary absorption band at 224 nm. If a solution of benzonitrile in water, with a concentration of 1x 10-4 molar, is examined at a wavelength of 224 nm, the absorbance is determined to be 1.30. The cell length is 1 cm? |
A. | |
B. | 2.3 x 10<sup>4</sup> |
C. | 3.3 x 10<sup>4</sup> |
Answer» D. | |
11. |
What is the correct order of λmax for π –> π* transition for the following three compounds?$ |
A. | R-C<span style="text-decoration:overline;">=</span>C-R > R<sub>2</sub>C = CR<sub>2</sub> > R-CHO |
B. | R-C<span style="text-decoration:overline;">=</span>C-R < R<sub>2</sub>C = CR<sub>2</sub> < R-CHO |
C. | R-C<span style="text-decoration:overline;">=</span>C-R = R<sub>2</sub>C = CR<sub>2</sub> = R-CHO |
D. | R-C<span style="text-decoration:overline;">=</span>C-R < R<sub>2</sub>C = CR<sub>2</sub> >R-CHO |
Answer» C. R-C<span style="text-decoration:overline;">=</span>C-R = R<sub>2</sub>C = CR<sub>2</sub> = R-CHO | |
12. |
What is the correct order of λmax for n –> π* transition for the R-CN, R-NO2, and R-N=N-R?$ |
A. | R-CN < R-NO<sub>2</sub> < R-N=N-R |
B. | R-CN = R-NO<sub>2</sub> = R-N=N-R |
C. | R-CN > R-NO<sub>2</sub> > R-N=N-R |
D. | R-CN > R-NO<sub>2</sub> < R-N=N-R |
Answer» B. R-CN = R-NO<sub>2</sub> = R-N=N-R | |
13. |
What is the correct order of λmax for n –> σ* transition?$ |
A. | R-OH > R-NH<sub>2</sub> > R-SH |
B. | R-OH < R-NH<sub>2</sub> < R-SH |
C. | R-OH > R-SH > R-NH<sub>2</sub> |
D. | R-OH < R-SH < R-NH<sub>2</sub> |
Answer» C. R-OH > R-SH > R-NH<sub>2</sub> | |
14. |
Which of the following comparison is correct for solvent shift on the n –>π* transition of acetone?$ |
A. | H<sub>2</sub>0 = CH<sub>3</sub>0H = C<sub>2</sub>H<sub>5</sub>0H = CHC1<sub>3</sub> = C<sub>6</sub>H<sub>14</sub> |
B. | H<sub>2</sub>0 > CH<sub>3</sub>0H > C<sub>2</sub>H<sub>5</sub>0H > CHC1<sub>3</sub> > C<sub>6</sub>H<sub>14</sub> |
C. | H<sub>2</sub>0 < CH<sub>3</sub>0H < C<sub>2</sub>H<sub>5</sub>0H < CHC1<sub>3</sub> < C<sub>6</sub>H<sub>14</sub> |
D. | H<sub>2</sub>0 > CH<sub>3</sub>0H < C<sub>2</sub>H<sub>5</sub>0H < CHC1<sub>3</sub> < C<sub>6</sub>H<sub>14</sub> |
Answer» D. H<sub>2</sub>0 > CH<sub>3</sub>0H < C<sub>2</sub>H<sub>5</sub>0H < CHC1<sub>3</sub> < C<sub>6</sub>H<sub>14</sub> | |
15. |
What is the wavelength range for UV spectrum of light? |
A. | 400 nm – 700 nm |
B. | 700 nm to 1 mm |
C. | 0.01 nm to 10 nm |
D. | 10 nm to 400 nm |
Answer» E. | |