Explore topic-wise MCQs in Organic Chemistry.

This section includes 14 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.

Which of the following is the slow, low-temperature, flameless form of combustion, sustained by the heat evolved when oxygen directly attacks the surface of a condensed-phase fuel?

A. Rapid combustion
B. Turbulent combustion
C. Spontaneous combustion
D. Smouldering
Answer» E.
Discussion
2.

The value ∆H transition of C (graphite) → C (diamond) is 1.9 kJ/mol at 25℃ entropy of graphite is higher than entropy of diamond. This implies that?

A. C(diamond) is more thermodynamically stable then C (graphite) at 25℃
B. C(graphite) is more thermodynamically stable than C (diamond) at 25℃
C. diamond will provide more heat on complete combustion at 25℃d) ∆Gtransition of C (diamon
D. is 1.9 kJ/mol at 25℃ entropy of graphite is higher than entropy of diamond. This implies that?a) C(diamond) is more thermodynamically stable then C (graphite) at 25℃b) C(graphite) is more thermodynamically stable than C (diamond) at 25℃c) diamond will provide more heat on complete combustion at 25℃d) ∆Gtransition of C (diamond) → C (graphit
E. → C (diamond) is 1.9 kJ/mol at 25℃ entropy of graphite is higher than entropy of diamond. This implies that?a) C(diamond) is more thermodynamically stable then C (graphite) at 25℃b) C(graphite) is more thermodynamically stable than C (diamond) at 25℃c) diamond will provide more heat on complete combustion at 25℃d) ∆Gtransition of C (diamond) → C (graphite) is -ve
Answer» E. → C (diamond) is 1.9 kJ/mol at 25℃ entropy of graphite is higher than entropy of diamond. This implies that?a) C(diamond) is more thermodynamically stable then C (graphite) at 25℃b) C(graphite) is more thermodynamically stable than C (diamond) at 25℃c) diamond will provide more heat on complete combustion at 25℃d) ∆Gtransition of C (diamond) → C (graphite) is -ve
Discussion
3.

The heat of combustion of carbon is 394 KJ/mol. What will be the heat evolved in combustion of 6.023 x 1022 atoms of carbon?

A. 64.7 KJ
B. 39.4 KJ
C. 42.4 KJ
D. 91.6 KJ
Answer» C. 42.4 KJ
Discussion
4.

Equal volumes of C2H2 & H2 are combusted under identical condition. What will be the ratio of heat evolved for C2H2 and H2?H2 (g) + 1/2 O2(g) → H2O(g), ∆H=-241.8 KJC2H2 (g) + 5/2 O2(g) → CO2(g) + H2O(g), ∆H=-1300 KJ

A. 5.37/1
B. 1/5.37
C. 1/1
D. 2.8/6.1
Answer» C. 1/1
Discussion
5.

Which of the following reaction has a faster rate of reaction for nascent oxygen atom?

A. R1 >> R2
B. R1 > R2
C. R1 << R2
D. R1 < R2
Answer» D. R1 < R2
Discussion
6.

THE_VALUE_‚ÄÖ√Ñ√∂‚ÀւĆ‚ÀÖ√∫H_TRANSITION_OF_C_(GRAPHITE)_‚ÄÖ√Ñ√∂‚ÀÖ√∫‚Àւ†_C_(DIAMOND)_IS_1.9_KJ/MOL_AT_25‚ÄÖ√Ñ√∂‚ÀÖ√´‚ÀÖ√¢_ENTROPY_OF_GRAPHITE_IS_HIGHER_THAN_ENTROPY_OF_DIAMOND._THIS_IMPLIES_THAT:?$#

A. C(diamond) is more thermodynamically stable then C (graphite) at 25‚ÑÉ
B. C(graphite) is more thermodynamically stable than C (diamond) at 25‚ÑÉ
C. diamond will provide more heat on complete combustion at 25‚ÑÉ
D. ∆G<sub>transition</sub> of C (diamond) → C (graphite) is -ve
Answer» E.
Discussion
7.

Which_of_the_following_is_the_slow,_low-temperature,_flameless_form_of_combustion,_sustained_by_the_heat_evolved_when_oxygen_directly_attacks_the_surface_of_a_condensed-phase_fuel?$

A. Rapid combustion
B. Turbulent combustion
C. Spontaneous combustion
D. Smouldering
Answer» E.
Discussion
8.

The heat of combustion of carbon is 394 KJ/mol. What will be the heat evolved in combustion of 6.023 x 1022 atoms of carbon?

A. 64.7 KJ
B. 39.4 KJ
C. 42.4 KJ
D. 91.6 KJ
Answer» C. 42.4 KJ
Discussion
9.

Equal volumes of C2H2 & H2 are combusted under identical condition. What will be the ratio of heat evolved for C2H2 and H2?

A. + 1/2 O<sub>2</sub>(g) → H<sub>2</sub>O(g), ∆H=-241.8 KJ
B. + 5/2 O<sub>2</sub>(g) → CO<sub>2</sub>(g) + H<sub>2</sub>O(g), ∆H=-1300 KJ
C. 5.37/1
D. 1/5.37
Answer» C. 5.37/1
Discussion
10.

With respect to enthalpy of combustion which of the following is correct?

A. ∆H<sub>rxn</sub> = Σ∆H<sub>f</sub> (product) – Σ∆H<sub>f</sub> (reactant)
B. ∆H<sub>rxn</sub> = Σ∆H<sub>f</sub> (reactant) – Σ∆H<sub>f</sub> (product)
C. ∆H<sub>rxn</sub> = Σ∆H<sub>f</sub> (product) + Σ∆H<sub>f</sub> (reactant)
D. ∆H<sub>rxn</sub> = 2 Σ∆H<sub>f</sub> (product) – Σ∆H<sub>f</sub> (reactant)
Answer» B. ‚Äö√Ñ√∂‚àö‚Ć‚àö√∫H<sub>rxn</sub> = ‚âà√≠¬¨¬£‚Äö√Ñ√∂‚àö‚Ć‚àö√∫H<sub>f</sub> (reactant) ‚Äö√Ñ√∂‚àö√ë‚àö¬® ‚âà√≠¬¨¬£‚Äö√Ñ√∂‚àö‚Ć‚àö√∫H<sub>f</sub> (product)
Discussion
11.

Which of the following statement is incorrect about oxidation number?

A. Show electron density and about the tendency of an atom or molecule to engage oxidation-reduction reactions
B. The oxidation number is always given in Roman numerals while the formal charge is always given in numbers
C. To calculate an oxidation number, it is essential to know which element in a chemical bond is the most electronegative
D. It cannot be a negative number
Answer» E.
Discussion
12.

What is the type of reaction between alkanes and hydroxyl radical?

A. endothermic
B. exothermic
C. isothermal
D. isochoric
Answer» C. isothermal
Discussion
13.

Which of the following is not true about combustion of hydrocarbons?

A. All hydrocarbons react in air to form carbon monoxide and then carbon dioxide
B. First step is always the reaction between the hydrocarbon and hydroxyl radical
C. Alkanes, the hydroxyl radical abstracts a hydrogen atom and forms a carbanion
D. With alkenes and alkynes, the electron-deficient hydroxyl radical adds to the multiple bond
Answer» D. With alkenes and alkynes, the electron-deficient hydroxyl radical adds to the multiple bond
Discussion
14.

What is the concentration of carbon dioxide in the atmosphere?

A. 3.5 x 10<sup>6</sup> ppm
B. 1.0 x 10<sup>2</sup> ppm
C. 1.6 x 10<sup>5</sup> ppm
D. 1.0 x 10<sup>3</sup> ppm
Answer» B. 1.0 x 10<sup>2</sup> ppm
Discussion