Bihar Board 12th Model Paper 2024 Download PDF
The Bihar School Examination Board (BSEB) has officially released the Model Question Papers for the 12th Board Examinations 2024. Science Students can access and download Chemistry, Physics, Maths, Biology, English and Hindi Model Papers in pdf directly from the below links and all others subjects model papers can download from official BSEB website: https://biharboardonline.bihar.gov.in/.
Bihar Board 12th Science Model Paper 2024
Chemistry Model Paper | Exam Date: 06.02.2024
Physics Model Paper | Exam Date: 03.02.2024
Biology Model Paper | Exam Date: 01.02.2024
Mathematics Model Paper | Exam Date: 02.02.2024
English Model Paper
Hindi Model Paper
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Bihar Board 12th Chemistry Model Paper 2024 Answer Key
| 1 - D | 15 - B | 29 - A | 43 - D | 57 - A |
| 2 - C | 16 - A | 30 - D | 44 - B | 58 - D |
| 3 - C | 17 - C | 31 - B | 45 - B | 59 - C |
| 4 - B | 18 - A | 32 - B | 46 - A | 60 - C |
| 5 - D | 19 - C | 33 - D | 47 - B | 61 - A |
| 6 - D | 20 - B | 34 - C | 48 - D | 62 - A |
| 7 - C | 21 - B | 35 - A | 49 - B | 63 - C |
| 8 - A | 22 - A | 36 - C | 50 - B | 64 - A |
| 9 - D | 23 - B | 37 - B | 51 - B | 65 - B |
| 10 - A | 24 - B | 38 - C | 52 - D | 66 - D |
| 11 - C | 25 - D | 39 - A | 53 - D | 67 - A |
| 12 - C | 26 - B | 40 - D | 54 - C | 68 - B |
| 13 - B | 27 - A | 41 - A | 55 - A | 69 - B |
| 14 - A | 28 - B | 42 - D | 56 - D | 70 - C |
Bihar Board 12th Chemistry Model Paper 2024 Short Question Answer
1. What are metallic solids ? Give two examples.
Metallic solids are composed of metal atoms that are held together by metallic bonds. Metallic solids are good conductor of heat and electricity. Examples are metals and metal alloys Cu, Fe, Zn, Ag, Ay, Cu – Zn etc.2. What are Frankel defects ? Explain with examples.
Frankel defect is shown by ionic solids. In this defect, the smaller ions are squeezed to an interstitial site . So, it generate a vacancy defect at its original site. Frenkel defect is also called dislocation defect. In this type of defect, density remains same. Frenkel defect is shown by ionic substance in which there is a large difference in the size of ions, for example, ZnS, AgCl, AgBr and AgI shows this effect due to small size of their cations.3. What are isotonic solutions ?
Two solutions having the same osmotic pressure at a given temperature are known as isotonic solutions. When such solutions are separated by semipermeable membrane no osmosis occurs between them.4. What are colligative properties of a solution ? Give examples.
colligative property is the property of dilute solution which do not depend on the chemical nature of the solute but depends only on the number of solute particles present in the solution.1. Relative lowering of vapour pressure
2. Osmotic pressure
3. Elevation of boiling point
4. Depression in freezing point
5. Define conductance and molar conductance.
The reciprocal of specific resistance (1/ρ) is called specific conductance or conductivity.Molar conductance is defined by the conducting power of all the ions produced by one mole of the electrolyte.
6. Write Faraday’s first law of electrolysis.
The amount of the substance deposited or liberated at any electrode is directly proportional to the quantity of electricity passed through it. It is equal to the product of current and time.If m grams of the substance is deposited on passing Q coulombs of electricity for a time t, then-
m ∝ Q
m ∝ I.t (as Q = I.t)
m = Z.I.t
Where Z is the electrochemical equivalent.
7. What are enzyme catalysts ?
Enzyme catalysts are biocatalysts that catalyse the biochemical reactions in living organisms. Enzyme catalysts usually increase the rate of biochemical reactions, which further result in the conversion of substrate into a product. It is very specific in nature and active under optimum conditions. There are mainly two types of enzyme catalysts – activation enzymes and inhibitory enzymes.8. What are surfactants ?
Surfactants are chemical compounds that are used in lowering the surface tension. They are amphiphilic in nature. Surfactant has both a water-insoluble component and a water-soluble component. Surfactants play an important role in cleaning, wetting, dispersing, emulsifying, foaming and anti-foaming agents.9. Write names and formulae of two ores of copper.
Two ores of copper are-1. Copper pyrite (CuFeS2
2. Malachite (CuCO3.Cu(OH)2
10. Differentiate between ores and minerals.
Ores are the Minerals from which metal can be extracted economically and conveniently. They do not have definite crystalline structure. All ores are not minerals. Example: Bauxite and Cryolite are the ores of Aluminium.Minerals are the natural inorganic substance that exist in earth’s crust. They have definite crystalline structure. All minerals are not ores. Example: Clay is the mineral of Aluminium.
11. Electron affinity of chlorine is greater than that of Fluorine. Why ?
Electron affinity of the chlorine is greater than that of fluorine because the size of fluorine is too small as size decreases from left to right inside the period, whereas chlorine has a larger size to accommodate electrons. Hence electron affinity of chlorine is more than that of fluorine.12. Halogen elements are strong oxidizing agents. Why ?
Halogens act as strong oxidising agents because they have high tendency to accept electron, i.e., they have high electron affinity values. The reduction potentials are high ( positive ).
13. What do you understand by interhalogens ? Give two examples.
Compounds containing two distinct forms of halogens are referred to as interhalogen compounds. Example: monofluoride chlorine, trifluoride bromine, pentafluoride iodide, heptafluoride iodide, etc.14. Discuss the structure of XeF2.
XeF2 has a linear structure with sp3d hybridization of central Xe atom and three lone pairs of electrons and two bond pairs of electrons.15. What are f-block elements ? Why are they called so ?
f- block elements are divided into two series, namely lanthanoids and actinoids, corresponding to the filling up of 4f and 5f orbitals. This block of elements are often referred to as inner transition metals. f- block elements are found outside at the bottom of the periodic table. The name f- blocks because the last electron enters into the f-orbital of the anti-penultimate shell.16. Cu(I) is diamagnetic where as Cu(II) is paramagnetic. Explain.
We know that-Cu (I) has electronic configuration- [Ar]3d10
Cu (II) has electronic configuration- [Ar]3d9
Cu (I) is diamagnetic because its d-subshell is fully filled. Cu (II) is paramagnetic because there is one unpaired electron.
17. Write IUPAC names of the following
(i) [CO(NH3)5Cl]Cl2 (ii) K3[Cr(C2O4)3]
(i) Pentaamminechloridocobalt (III) chloride(ii) Potassium trioxalato chromate(III)
18. What are different constituents of tincture iodine?
It is usually 2–7% elemental iodine, along with potassium iodide or sodium iodide, dissolved in a mixture of ethanol and water.19. What are elastomer ? Give one example of natural elastomer.
Elastomers are synthetic rubber. In these elastomeric polymers, the polymer chains are held together by the weakest intermolecular forces. These weak binding forces permit the polymer to be stretched. A few ' crosslinks' are introduced in between the chains, which helps the polymer to retract to its original position. Examples are starch, cellulose, proteins, nucleic acids and natural rubber.20. Define carbohydrates.
Optically active polyhydroxy aldehydes or ketones or the compounds which produce such type of units on hydrolysis is called carbohydrate. The general formula for carbohydrates is Cx(H2O)y. Where x and y may be same or different. Examples of carbohydrate foods are milk, yogurt, bread, rice, potatoes, corn, whole fruits or fruit juice, candies, cookies, etc.For more practice papers, Notes, MCQs, PYQs CLICK HERE