12-Chemistry Questions

Chemistry- 12 Questions NEB format

SET A

Group-“A”

1.  How do you predict the molecular geometry of NH3 based on VSEPR Model.

2. The solubility product constant of BaSo4 in water at 250 C is 1 X 10-10
    MolL-1 .Calculate the solubility of BaSo4 in g/L.

3. Define primary and secondary solution with example.

4. Define single electrode potential and E.C.E?

5. What is meant by Enthalpy of reaction?
Calculate the enthalpy of formation of NH3 from the following equation.
N2 (g) 3H2   ↔  2NH2 (g)

6. Distinguish spontaneous and Non-spontaneous process giving an example of each.

7. What is meant by instaneous rate of reaction? Write the expression for the rate of the following reaction:
2N2 o5 (g)       →     4NO2 (g) + O2 (g)

8. Define Huckel’s rule for aromaticity.

9. Write an example of carbylamines reaction and coupling reaction?

10. Write the possible isomeric amines of C2 H9 N and give their IUPAC names.

11. Why does Nitrobenzene undergo electrophilic substitution reaction at a meto position.

12. Why is chloro acetic acid stronger than acetic acid?

13. Write an example of each of the following??
a. Cannizzaro’s reaction         b. DNP test.

14. How does Meathanol react with 1.) NH3   and conc. NaOH

15.  What is willianson’s etherification reaction?

16. Why does phenol react with 1) aq. Br2    2) Benzene Diazonium

17. Name the Isomer of C3H8O which undergoes iodoform test.

18. Why is nucleophilic substitution difficult in Halo-arenes?

19. What happens when protein is 1.) Heated       2.) Hydrolysed.

20. What are the difference between DNA and RNA?

21. Distinguish between Addition and condenser polymer with an example of each.

22. What is difference between an antiseptic and antipyretic drug?

23. Why does silver nitrate permanent black strain on the skin in presence of sun-light.  Write an impulse of it.

24. Difference between tempering of steel and quenching.

25. What is Nessler’s Reagent? How is it prepared?

26. How is red oxidic of Copper converted into block oxide of copper and vice versa?

27. Write down the structure of secondary halo-alkane of C3H7X. What happens when the secondary halo-alkane is heated with Na in presence of dry ether.

Group-“B”

Attempt any Five questions:

23.  Define acidity of base giving an example.  0.8 gm of divalent Metal was dissolved in 100cc of 1.28 NHcl and the solution was diluted to 200 cc. 50 cc of this dilute solution required 54.6 cc of 0.22N NaoH for neutralization. Calculate the atomic Mass of that Metal.

24.  How is anhydrous formic acid prepared in the lab? Why does formic acid give Silver Mirror with Tollens reagent?

25.  Write down a chemical reaction to distinguish ethanamine from N- methylmethaneamine? How is ethanamine prepared from:- 1) Proponamide      2.) ethanenitrile.

26. How is blister of copper obtained from copper pyrites?

27. How is trichloro-methane prepared in the lab? Write its action upon acetone.

28. From the following experimental data for the reaction:
2A+B    →  2AB

Experiment [A]MolL-1 [B] MolL-1 Rate Mol-1  s-1
1 0.5 0.5 1.6 x 10-4
2 0.5 1 3.2 x 10-4
3 1 1 3.2 x 10-4

I. Find overall order of reaction.
II. Find the rate constant.

29.    What is meant by enthalpy of combustion? Enthalpy of formation of benzene is 55kJ. Enthalpy of formation of water and Carbon dioxide are -395KJ and -285KJ respectively. Calculate the enthalpy of combustion of Benzene.

Group “C”    2 x 10=20

30. How is nitrobenzene prepared in lab? Indetify A,B, C,D and E in the following sequence of reaction.
Refer To: Page 223 [2066 Q. No 28]{From Set “Asmita”(2076)}

31.  How would you distinguish propan-2-ol from 2-methypropan-2-ol by using Victor meyer’s Method. An alkene Ạ undergoes ozonolysis to give two carbonyl compound B and C. The compound B on reduction with zn-Hg/H+ gives propane. The compound C react with HCN and followed by hydrolysis to produce 2-hydroxyproponic acid as the major product. Write chemical reaction involved and give IUPAC name of A,B and C.

32. Define the term:-CF

a.)  Ostwald dilution law.
b.)  Degree of ionization
c.) Ionic product of water.
d.) Common ion effect
e.) PH value of a solution.
Why is Ostwald dilution law not applicable to stop electrolyte. What mass of KOH should be dissolved in one lit of solution to prepare a solution having PH is 12 at 250 C?( At. Wt of K =39)

33. Write short notes on:

a.) State and explain faraday’s law of electrolysis.
b.) Application of solubility product and common ion effect.
c.) Manufacture of steel by open-hearth process
d.) Chemistry of corrosive sublimate.
e.) Distinction of 1,2and 3 degree  alcohol by victor method.

Best of Luck!

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