Latest questions in this category.
The Carius method involves heating the compound with fuming HNO₃ to convert halogens to silver halides.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
Kjeldahl’s method involves heating the compound with H₂SO₄ to form (NH₄)₂SO₄, followed by ammonia liberation and titration.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
Kjeldahl’s method fails for nitro compounds (-NO₂) as nitrogen is not easily converted to NH₃; Dumas method is preferred.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
Molar mass of BaSO₄ = 233 g/mol, S = 32 g/mol. Mass of S = (32/233) × 0.505 = 0.069 g. Percentage = (0.069/0.15) × 100 = 46%.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
CH₂=CHC≡CH fits C₅H₆. The fourth carbon (C≡) is sp, with a 180° angle.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
Mass of N = (28/22400) × 70 = 0.0875 g. Percentage = (0.0875/0.3) × 100 ≈ 29.17% ≈ 29%.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
Molar mass of AgCl = 143.5 g/mol, Cl = 35.5 g/mol. Mass of Cl = (35.5/143.5) × 0.235 = 0.058 g. Percentage = (0.058/0.2) × 100 = 29%.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
s-character: sp (50%) > sp² (33%) > sp³ (25%). CH₃C≡CH has an sp-hybridized carbon in the triple bond.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
In Kjeldahl’s method, nitrogen is converted to NH₃ (ammonia), which is then titrated with acid.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
Molar mass of AgCl = 143.5 g/mol, Cl = 35.5 g/mol. Mass of Cl = (35.5/143.5) × 0.287 = 0.071 g. Percentage = (0.071/0.18) × 100 ≈ 39.44% ≈ 40%.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
Molar mass of BaSO₄ = 233 g/mol, S = 32 g/mol. Mass of S = (32/233) × 0.583 = 0.08 g. Percentage = (0.08/0.25) × 100 = 32%.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
Mass of N = (28/22400) × 84 = 0.105 g. Percentage = (0.105/0.4) × 100 = 26.25%. (Carius data is a distractor for chlorine.)
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Qualitative and Quantitative Analysis - Lassaigne Test and Estimation
