9 public questions tagged with this topic.
Aniline forms a diazonium salt with NaNO₂ and HCl , which reacts with KI to form C₆H₅I (iodobenzene).
Ref: NCERT Class 12 Chemistry > Chapter 6: Haloalkanes and Haloarenes > Topic: Polyhalogen Compounds - Chloroform Iodoform DDT Freons
Cr (+6 in Cr₂O₇²−) to +3 in CrCl₃: 4 Cr gain 12 electrons. Cl (-1 to 0): 6 Cl lose 12 electrons. Total = 12.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Oxidizing and Reducing Agents and Strength
Mn (+7 in KMnO₄) becomes +2 in MnCl₂, gaining electrons; it’s the reduced species.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Electrode Potential and Electrochemical Series and Galvanic Cells
After mixing: [HCl] = 0.05 M , [A-] = 0.025 M , [HA] negligible due to common ion effect. Ka = ([H+][A-]/[HA]) , [H+] ≈ 0.05 , pH = -log(0.05) = 1.3 .
Ref: NCERT Class 11 Chemistry > Chapter 6: Equilibrium > Topic: Buffer Solutions and Solubility Product and Common Ion Effect
In HCl , hydrogen and chlorine share one electron pair, forming a single covalent bond.
Ref: NCERT Class 11 Chemistry > Chapter 4: Chemical Bonding and Molecular Structure > Topic: Ionic Bonding - Lattice Enthalpy and Properties of Ionic Compounds
M₁V₁ = M₂V₂. 0.25 × 200 = M₂ × (200 + 300). M₂ = (0.25 × 200)/500 = 0.1 M.
Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Laws of Chemical Combination - Conservation Mass Definite Multiple
M₁V₁ = M₂V₂. 0.4 × 100 = M₂ × (100 + 200). M₂ = (0.4 × 100)/300 ≈ 0.133 M.
Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Importance and Nature of Chemistry and Properties of Matter
Reaction: MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂. Moles of Cl₂ = 1.42/71 = 0.02 mol. 1 mol Cl₂ needs 1 mol MnO₂; 0.02 mol needs 0.02 × 87 = 1.74 g.
Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Dalton's Atomic Theory and Atomic and Molecular Masses
90mL is obtained by applying the relevant formula or quantitative relationship to the given parameters. In Water and Mole Concept, numerical problem-solving requires understanding the mathematical relationships between biological variables. The calculation involves substituting the provided values into the appropriate equation and solving systematically. The other options (10mL, 100mL, and 990mL) result from common calculation errors such as using incorrect formulas, misidentifying variables, inverting ratios, or making arithmetic mistakes.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 2
