Organic Chemistry - Some Basic Principles and Techniques appeared 101 times across 3 years — 11.8% of Chemistry.
This question is from Quantitative Analysis - Dumas Method.
During estimation of nitrogen by Dumas' method of compound X (0.42 g):
The image shows the molecular skeletal architecture of compound X with structural parameters revealing a formula corresponding to a molecular mass of 86 g/mol.
mL of N2$N{2}$ gas will be liberated at STP. (nearest integer)
(Given molar mass in g mol: C: 12, H: 1, N: 14)
The image shows the molecular skeletal architecture of compound X with structural parameters revealing a formula corresponding to a molecular mass of 86 g/mol.
Numerical Answer Type:
Enter a numerical valueAnswer: 111 to 111+4 marks
Solution & Explanation
Related Formula
Using the Principle of Atom Conservation (POAC) for Nitrogen:
ncompound × (atoms of N per molecule) = 2 × nN₂$$n_{\text{compound}} \times (\text{atoms of N per molecule}) = 2 \times n_{\text{N}_2}$$
Core Logic
The molecular weight of the given heterocyclic amine organic structure X$X$ (piperazine, C₄H₁₀N₂$\text{C}_4\text{H}_{10}\text{N}_2$) is calculated as:
The image shows the molecular skeletal architecture of compound X with structural parameters revealing a formula corresponding to a molecular mass of 86 g/mol.
Given mass of compound = 0.42 g$= 0.42\text{ g}$:
Moles of compound X = (0.42)/(86) mol$$\text{Moles of compound } X = \frac{0.42}{86}\text{ mol}$$
Step 1: Calculating STP Volume
Since each molecule contains 2$2$ nitrogen atoms, 1 mol$1\text{ mol}$ of compound produces 1 mol$1\text{ mol}$ of N₂$\text{N}_2$ gas:
Using standard molar volume at STP (22700 mL/mol$22700\text{ mL/mol}$ per IUPAC convention, or 22400 mL/mol$22400\text{ mL/mol}$ in traditional calculations):
Volume of N₂ at STP = (0.42)/(86) × 22700 mL ≈ 110.86 mL ≈ 111 mL$$\text{Volume of } \text{N}_2\text{ at STP} = \frac{0.42}{86} \times 22700\text{ mL} \approx 110.86\text{ mL} \approx 111\text{ mL}$$
(Note: If calculated using 22400 mL/mol$22400\text{ mL/mol}$, Volume = (0.42)/(86) × 22400 ≈ 109.4 mL ≈ 109 mL$\text{Volume} = \frac{0.42}{86} \times 22400 \approx 109.4\text{ mL} \approx 109\text{ mL}$.)
Rounding to the nearest integer gives 111 (official accepted range: 109 to 111).
Pattern Recognition
Shortcut: Determine the molar mass (M = 86 g/mol$M = 86\text{ g/mol}$) and nitrogen atom count (2 N atoms 1 mol N₂ per mol of compound$2\text{ N atoms} \implies 1\text{ mol } \text{N}_2\text{ per mol of compound}$). Multiply moles directly by molar volume at STP to find the liberated gas volume.
Evaluation Rubric / Model Answer
111
Chapter Mix
Class 11 Chemistry: Organic Chemistry - Some Basic Principles and Techniques
The image shows the molecular skeletal architecture of compound X with structural parameters revealing a formula corresponding to a molecular mass of 86 g/mol.
Keywords:#Dumas method quantitative#Molar weight tracking#Nitrogen gas evolution
More Organic Chemistry - Some Basic Principles and Techniques Previous-Year Questions
Q58jee_main_2026_21_jan_morningQuantitative Analysis of Elements
In Carius method, 0.75 g of an organic compound gave 1.2 g of barium sulphate, find percentage of sulphur (molar mass 32 g mol⁻¹$32\text{ g mol}^{-1}$). Molar mass of barium sulphate is 233 g mol⁻¹$233\text{ g mol}^{-1}$.
A.4.55%$4.55\%$
B.10.30%$10.30\%$
C.21.97%$21.97\%$
D.16.48%$16.48\%$
Solution
Related Formula
Percentage of Sulphur = Mass of S in BaSO₄Molar mass of BaSO₄ × Mass of BaSO₄ formedMass of organic compound × 100$$\text{Percentage of Sulphur} = \frac{\text{Mass of } S \text{ in } BaSO_4}{\text{Molar mass of } BaSO_4} \times \frac{\text{Mass of } BaSO_4 \text{ formed}}{\text{Mass of organic compound}} \times 100$$
Core Logic
Molar mass of BaSO₄$BaSO_4$ = 233 g/mol.
Mass of Sulfur (S) in 1 mole of BaSO₄$BaSO_4$ = 32 g.
Mass of BaSO₄$BaSO_4$ formed = 1.2 g.
Mass of organic compound = 0.75 g.
Class 11 Chemistry: Organic Chemistry - Some Basic Principles and Techniques
Q62jee_main_2026_21_jan_morningResonance Effects
From the following, the least stable structure is :
A.Option 1$\text{Option 1}$
B.Option 2$\text{Option 2}$
C.Option 3$\text{Option 3}$
D.Option 4$\text{Option 4}$
Solution
Core Logic
In structure 3, there are positive formal charges on two adjacent atoms (Oxygen and the Carbon adjacent to it). Like charges on adjacent atoms cause extreme electrostatic repulsion, making the structure highly unstable.
Resonance Effects diagram for Q62 - JEE Main 2026 Morning
Pattern Recognition
Rules of resonance stability:
Complete octets are more stable.
More covalent bonds = more stable.
Least charge separation is more stable.
Like charges on adjacent atoms create massive destabilization (Least stable scenario).
Chapter Mix
Class 11 Chemistry: Organic Chemistry - Some Basic Principles and Techniques
Q66jee_main_2026_21_jan_morningIsomerism
Identify correct statement from the following:
A. Propanal and propanone are functional isomers.
B. Ethoxyethane and methoxypropane are metamers.
C. But-2-ene shows optical isomerism.
D. But-1-ene and but-2-ene are functional isomers.
E. Pentane and 2, 2-dimethyl propane are chain isomers.
Choose the correct answer from the options given below:
A.B, C and D only$\text{B, C and D only}$
B.A, B and C only$\text{A, B and C only}$
C.A, B and E only$\text{A, B and E only}$
D.C, D and E only$\text{C, D and E only}$
Solution
Core Logic
A. Propanal (CH₃CH₂CHO$CH_3CH_2CHO$) and propanone (CH₃COCH₃$CH_3COCH_3$) have different functional groups (aldehyde vs ketone) but the same molecular formula. They are functional isomers. (Correct)
B. Ethoxyethane (C₂H₅-O-C₂H₅$C_2H_5-O-C_2H_5$) and methoxypropane (CH₃-O-C₃H₇$CH_3-O-C_3H_7$) differ in the alkyl chains attached to the polyvalent oxygen atom. They are metamers. (Correct)
C. But-2-ene shows geometrical isomerism (cis-trans), but no optical isomerism as it lacks a chiral center. (Incorrect)
D. But-1-ene and but-2-ene differ in the position of the double bond. They are position isomers, not functional isomers. (Incorrect)
E. Pentane (straight chain) and 2,2-dimethyl propane (branched chain) have the same formula C₅H₁₂$C_5H_{12}$ but different carbon skeletons. They are chain isomers. (Correct)
Correct statements: A, B, and E.
Pattern Recognition
Metamerism arises when there is a difference in the alkyl groups attached to a polyvalent functional group (e.g., -O-, -S-, -NH-, -CO-).
Chapter Mix
Class 11 Chemistry: Organic Chemistry - Some Basic Principles and Techniques
A. 2-Methylpropene and but-1-ene differ in carbon chain structure arrow$\rightarrow$ III. Chain isomers
B. Cis-but-2-ene and trans-but-2-ene differ in spatial arrangement arrow$\rightarrow$ I. Stereoisomers
C. 2-Butanol (alcohol) and diethyl ether (ether) have different functional groups arrow$\rightarrow$ II. Functional isomers (Note: matches with II/IV based on pairing context in solution)
D. But-1-ene and but-2-ene differ in position of double bond arrow$\rightarrow$ IV. Position isomers
Nucleophilicity generally parallels basicity among related species (when comparing oxygen-centered nucleophiles in similar environments). Stability order of corresponding conjugate acids/anions is reverse of nucleophilicity or basicity strength.
Basicity/Nucleophilicity order: ^-OH > PhO^- > CH₃COO^- > ClO₄^-$^-\text{OH} > \text{PhO}^- > \text{CH}_3\text{COO}^- > \text{ClO}_4^-$.
Step 1: Final Conclusion
Thus, option (4) represents the correct nucleophilicity order.
Pattern Recognition
Sees: Nucleophilic substitution rate and nucleophilicity order.
Trap: Confusing leaving group ability with nucleophile strength.
Chapter Mix
Class 11 Chemistry: Organic Chemistry - Some Basic Principles and Techniques
Practice past-year questions one chapter at a time. Pick an exam → subject → chapter and get every PYQ for that topic — pulled together from all past papers — with the chapter's key formulas alongside.
 "Dumas method quantitative, Molar weight tracking, Nitrogen gas evolution")
 "Dumas method quantitative, Molar weight tracking, Nitrogen gas evolution")
