CHEMISTRY-25-02- 11th (PQRS & J) Partial Marking
CHEMISTRY FINALTEST PART -A Q.1 If % ionic character of O–H bond is 10% & O–H bond distance is 1 4.8 Å, then calculate dipole moment of H2O molecule (in Debye) given H–O–H bond angle is 105°. [Use sin 52.5° = 0.8] [5] [Ans. 0.12 D] [Sol. q × d = 4.8 × 10–10 × 0.1 × 1 × 10–8 4.8 = 0.1 × 10–18 ese cm = 0.1 D {2} net = 2 cos 52.5 = 2 × 0.1 × (1 – 0.64) D = 2 × 0.1 × 0.6 net = 0.12 D {3} 2 Marks if only bond dipole is calculated ] Q.2 Arrange in ascending order (reasons not required) (a) | Hhydrogenation| of : 1, 2 Pentadiene, 1, 3 Pentadiene & 1, 4 Pentadiene (b) Ionic conductance of : F–, Na+ & Cs+. (c) Dipole Moment of : , , , (d) Boiling point : n-pentane, isopentane, neo-pentane [1.5+1+1.5+1] [Sol.(a) Reasons not required for marks. No marks for partially correct order. (1) (2) (3) C = C = C – C – C, C = C – C = C – C, C = C – C – C = C Most stable (2) > (3) > (1) |HHE| (2) Tcritical, T = Tcritical, T