12th Chemistry Public Exam Model Question Paper 2022

PART – A

ii)     Choose and write the correct answer

iii)    Each question carries one mark                                15x1=15

1.     Ammonia Leaching is suitable for

a)  Aℓ                          b) Zn                                     c) Ag                          d) Ni

2.     The element that does not show catenation

a)  C                            b) Si                                      c) Pb                          d) Ni

3.     The hybridization of AX5 interhalogen compound

a)  sp3                                                   b) sp3d                       c) sp3d2                                             d) sp3d3

4.     The actinoid element which shows +7 oxidation state.

a)  Am                        b) Cf                                     c) No                         d) Lr

5.     Oxidation state of central metal ion in the complex [Cr(CN)5(Cℓ)]-4 is

a) +1                          b) +2                                     c) +3                          d) +4

6.     An example for ionic crystal is

a)  CO2                                                b) Ni                                     c) KCℓ                       d) H2O

7.     Unit of zero order rate constant is

a)  sec−1                                              b) mol Lit−1                                                        c) mol Lit−1 sec−1                   d) None

8.     pH of 10−3M HCL solution is

a) 3                            b) −3                                     c) 11                          d) −11

9.     The unit of cell constant

a)  ohm                       b) ohm−1                                                                c) cm−1                                               d) ohm cm−1

10. Which of the following is used as antifreeze in automobile radiator

a)  Methanol               b) ethanol                              c) ethylene glycol       d) Glycerol

11. The product formed in Kolbe reaction

a)  Salicylaldehyde     b) Salicylic acid                     c) Phenolphthalein     d) Picric acid

12. Which one of the following reaction is an example of disproportionation reaction

a)  Aldol condensation b) Cannizzaro reaction c) Benzoin condensation d) None of these

13. Secondary Nitro Alkanes react with HNO2 to give

a)  Red solution           b) Yellow solution                 c) Green solution        d) blue solution

14. Which one of the following rotates the plane polarised light towards left?

a)  D(+) glucose          b) L(+)Glucose                      c) D (−) Fructose        d) (+) Galactose

15. The most effective electrolyte for the coagulation of AS2S3 Sol is

a)   NaCl                     b)Ba(NO3)2                                                      c) K3[Fe(CN)6]          d) Aℓ2(SO4)3

Part-B

Note: Answer any six questions:                                   6x2=12

Q.No: 24 is compulsory

16.Differentiate roasting and smelting

17.  What is the hybridization of iodine in IF7? Draw its structure. 18.Differentiate primary and secondary valencies of coordination compounds.

19.Rate constant of first order reaction is 1.54x10−3s−1. Calculate its half life period. 20.State Kohlransh law.

21.How will you distinguish phenol from alcohol? 22.Write the dehydration reaction of glycerol.

23.Why aniline does not undergo Friedel craft reaction? 24.Explain the structure of Lactose.

Part –C

Note: i) Answer any Six question of the following questions:-

ii) Q.No:33 is compulsory                                    6x3=18

25. What is burnt alum? Write its preparation.

26.  What are inner transition elements? Give an example. 27.What is point defect? Write its classification.

28.Derive the relationship between pH and pOH. 29.Why colloids to be purified?

30.Write a note on crossed aldol condensation reaction. 31.Identify A,B and C is the following reaction.

C6H5CONH2

—^B—^r2 → A —^H—^NO—2 → B —^H—2O—→

KOH                                H+

32. How fructose reacts with Na-Hg/H2O?

33. Find the pH of a buffer solution containing 0.15 more per litre of CH3COONa and 0.15 mole per litre of CH3COOH. Ka for acetic acid is 1.8x10–5.

Part –D

Note:  Answer all the questions                                   5x5=25

34. a)      i) Explain electromagnetic separation method. (3)

ii) Write the preparation of borax. (2)