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#### Model 5 Mark Book Back Questions (New Syllabus) 2020

12th Standard EM

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 90

Part A

18 x 5 = 90
1. The selection of reducing agent depends on the thermodynamic factor: Explain with an example.

2. A hydride of 2nd period alkali metal (A) on reaction with compound of Boron (B) to give a reducing agent (C). identify A , B and C.

3. Deduce the oxidation number of oxygen in hypofluorous acid – HOF.

4. Why do zirconium and Hafnium exhibit similar properties?

5. Why first ionization enthalpy of chromium is lower than that of zinc?

6. What is crystal field stabilization energy (CFSE)?

7. Aluminium crystallizes in a cubic close packed structure. Its metallic radius is 125pm. calculate the edge length of unit cell.

8. The rate constant for a first order reaction is 1.54x 10-3 s-1. Calculate its half life time.

9. The rate constant of a reaction at 400 and 200K are 0.04 and 0.02 s-1 respectively. Calculate the value of activation energy

10. Ksp of AgCl is $1.8\times10^{-10}$. Calculate molar solubility in 1 M AgNO3

11.  Calculate the standard emf of the cell: Cd|Cd2+||Cu2+|Cu and determine the cell reaction.
The standard reduction potentials of Cu2+|Cu and Cd2+|Cd  are 0.34V and -0.40 volts
respectively. Predict the feasibility of the cell reaction.

12. Write a note on sacrificial protection.

13. Comment on the statement: Colloid is not a substance but it is a state of substance.

14. An organic compound (A) of molecular formula C6H6O gives violet colour with neutral FeCI3. (A) gives maximum of two isomers (B) and (C) when an alkaline solution of (A) is refluxed with CCI4 (A) also reacts with C6H5N2CI to give the compound (D) which is red orange dye. Identify (A), (B), (C) and (D). Explain with suitable chemical reactions.

15. Write the structure of the major product of the aldol condensation of benzaldehyde with acetone.

16. A Monoobromoderivative (A) on treatment with KCN followed by acid hydrolysis and heating gives a monobasic acid (B) along with liberation of CO2 . (B) on heating with liquid ammonia followed by treating with Br2 /KOH  gives (c) which on treating with NaNO2 and HCl at low temperature followed by oxidation gives a monobasic acid (D) having molecular mass 74. Identify A to D.

17. Writhe the structure of α-D (+) glucophyranose

18. Write a note on co –polymer