X-CHEMISTRY Guess Paper 2025

 




Total marks: 60 
 Time: 3 Hours

General Instructions

Section – A; contains 12 MCQs and all of them are to be answered.

Section – B; consists of 12 short-answer questions of which 8 are to be answered (24 marks)

Section – C; consists of 6 Long-answer questions of which 4 are to be answered (24marks)






 


1. For the reaction, 2A(g)   +  B(g) ⇌ 3C(g) the expression for the equilibrium constant is:

(a) [2A][B]/[3C]                      

(b) [A]2[B]/[C]3                             

(c) [3C]/[2A][B]                            

(d) [C]3/[A]2[B]

 

2. Equilibrium constant value “Kc“ is equal to;

(a) Qc/Kr                                   

(b) Kr /Kf                                         

(c) Kc/Qc                                          

(d) Kf/Kr 

 

3. NH3 can be a base according to

(a) Arrhenius theory             

(b) Bronsted-Lowry theory       

(c) Lewis theory                        

(d) both b and c

 

4. Which of the following is a Lewis base?

(a) HNO3                                   

(b) AlCl3                                         

(c) HCl                                       

(d) CN

 

5. The general formula of alkynes is

(a) CnH2n                                   

(b) CnH2n+1                                      

(c) CnH2n–2                                      

(d) CnH2n+2

 

6. Which of the following is an alcohol?

(a) CH3CHO                              

(b) CH3CH2OCH3                          

(c) CH3CH2OH                                       

(d) HCOOH

 

7. Which one of the following is polysaccharide?

(a) Fructose                              

(b) maltose                                     

(c) starch                                      

(d) None

 

8. cellulose content in Cotton is

(a) 70%                                      

(b) 95%                                           

(c ) 85%                                       

(d) 90%

 

9. Ozone layer is part of

(a) stratosphere                      

(b) mesosphere                             

(c) thermosphere                         

(d) troposphere 

 

10. It used to assess concentration or amount of given atomic, molecular or ionic chemical.

(a) Chromatography             

(b) Spectroscopy                          

(c) Conductometry                       

(d) Potentiometry

 

11. Surfactants reduce the......... of water.

(a) Surface tension                  

(b)  Viscosity                                 

(c) Boiling point                            

(d) Melting point

 

12. The centrifuge machine used for separation of:

(a) Crystal                                 

(b) pH                                               

(c) Mud                                     

(d) Juice

 

13. Insulin which enables our body to use glucose obtained from food or glycogen is basically:

 (a) an enzyme                          

(b) a hormone                               

(c) an starch                            

(d) a mineral

 

14. Vital force theory was introduced by

(a) Robert Boyle                      

(b) J. J. Berzelius                            

(c) Lewis                                      

(d) Wohler 

 

15. Lactose enzymes are used:

(a) in production of bread                                 

(b) to make ice cream sweeter                                  

(c) to make alcohol                                              

(d) to maintain colour

 





1. Define any three of the following:

equilibrium constant, reaction quotient, extent of a reaction, pH, Indicator, Neutralization, Titration, alicyclic compounds, aromatic compounds, catenation, aldoses, ketoses, saccharides, functional group, Peptide linkage, saponification, lipids, enzymes, isomerism, Bloor’s reagent, fatty acid, ozone hole, organic chemistry, Biochemistry, Environmental chemistry, Analytical Chemistry, Qualitative Analysis, Quantitative Analysis,  accuracy, precision,  titrant, analyte, Indicator, parameter

 

2. Write down three differences between any one of the following:

 (i)    Troposphere and Stratosphere                        

(ii)   reversible and irreversible reactions

(iii)  saturated and unsaturated hydrocarbons  

(iv)   Dextrorotary and Levorotatory Sugars

(v)Quantitative analysis and qualitative analysis          

(vi)Titrimetric analysis and gravimetric analysis

(vii)Classical and Instrumental Methods               

(viii) fat and water-soluble vitamins.

(ix) DNA and RNA         

(viii) fat and oil

 

3.Define chemical equilibrium state. Why chemical equilibrium is dynamic? Explain it with one examples

OR

Describe the characteristics of equilibrium constant. Why equilibrium constant may or may not have unit? Justify       with example.

 

4.  Write down Equilibrium Constant Expression (Kc) and unit of Kc for any 3 of the following balanced reversible reactions.

(i)     N2(g) + 2O2(g)  2NO2(g)                              

(ii) H2(g) + I2(g)  2HI(g) 

(iii)  CO2(g) + H2(g)  CO(g) + H2O(g)                    

(iv) 2SO2(g) + O2(g)   2SO3(g)

(v)  N2(g)  + 3H2(g)     2NH3(g)                

(vi) CO(g)  + 3H2(g)   CH4(g) +  H2O(g)

 

5.  A solution of HCl has pH of 2.3. Calculate its pOH and [H+]?

OR 

Find pH, pOH, [OH] and [H+] of 2.46 × 10−9 M KOH solution.

 

6. State vital force theory and how was this theory discarded by Wohler?  

 Or

Write the names and structural formulae of six carbons alkanes, alkenes, alkyne, cycloalkane and aromatic hydrocarbons. 







 

8.      Define salt and its three types with two examples each. Give three uses of salts. Also write any three methods of preparation of salts with equation.

OR

Write one use of enzymes yeast, cellulose and amylase.

 

9. Elaborate ionization equation of water. Explain in detail that how water ionization is related with pH of solution?

OR 

Define buffers. What is the composition of buffers? Discuss its importance in our daily life.     

10.  What are amino acids and peptide bond? How peptide bond is formed? Also explain dipeptides & tripeptides.

OR

What is homologous series? Name the any two common homologous series with examples. Write down the general characteristics of homologous series.

OR

What is alkyl radicals? Give its type and general formula. Explain with structure different radicals of propane &  butane.

 

11.   Give reason:

(i)    Why Silicon compounds are lesser than that of Carbon compounds?

(ii)   Why pure water is considered as weak electrolyte?

(iii) Justify the petroleum is ‘black gold’.

(iv) Alkanes are said to be saturated hydrocarbons.

(v) Justify that water soluble vitamins are not injurious to health.

(vi) Justify that greenhouse effect leads to global warming

(vii) Justify that “water is solvent”.

(viii) How is vegetable oil is converted into saturated fat (ghee)?

(ix) Why chemical equilibrium is considered dynamic not static?

(x) Why the temperature on top of a mountain is colder than at sea level?






 








13.   What are Oligosaccharides, Disaccharides and polysaccharides. Give their examples and sources.

OR

What are the carbohydrates? Explain sources and types of carbohydrates.

 

14.   What are amino acids and give their general structure? How many Essential and Non-essential Amino acids are   there? Write down the range of Number of Amino acids and molecular weights of Proteins

OR

What are fatty acids? Give their examples and chemical nature.

 

15.   Briefly describe any three beneficial impacts of Pharmaceutical industry on human society.

 

16.   Write down causes of following diseases:

(i) Diarrheal Diseases        

(ii) Dysentery                 

(iii) Cholera               

(iv)   Crytosporidium

(v) Fluorosis                         

(vi) Hepatitis                  

(vii) Hookworm          

(viii) Typhoid

 

17.   What is the cause of acid rain? Explain. Write down the effects of acid rain.

OR

What are primary and secondary air pollutants? Or Give difference between primary and secondary air     pollutants. Identify as primary or secondary air pollutant SO2, CH4, HNO3, NH3, H2SO4 and O3

 

18.Describe the composition of water. Write degree of Hardness of water on the basis of Dissolved Ca Ions (mg/L)

 

19. List down the applications of conductometry? 

 

20. What is error? Write down causes of errors with their %. Write down brief note systematic and random errors with two examples each. 







22.   State law of mass action and define Kc. Derive an expression for equilibrium constant for a general reaction.

 

23.   State and explain Bronsted-Lowry acid-base theory or Lewis concept of acids and bases with examples? explain            with an example that water is a Bronsted-Lowry acid as well as Bronsted-Lowry base. 

OR

State three different theories about concepts of acids and bases with one examples and also indicate one      limitation of each concept. Which of the following is/are Arrhenius acids and bases?

(a) Ca(OH)2                           

(b) HNO3                          

(c) NaOH                     

(d) H2SO4                 

 

24. Define functional group. Write different functional groups which contain carbon, hydrogen and oxygen.

OR 

Define nomenclature and describe IUPAC nomenclature rules for alkynes and alkanes. Write down IUPAC names of following: 










25. Define functional group. Write different functional groups which contain carbon, hydrogen and oxygen.

OR

What are the main sources of organic compounds? Mention with special reference of coal, petroleum and natural gas.

OR 

What do you mean by diversity and magnitude of organic compounds? Give at least 5 reasons. 


26. What are Lipids? Write down the sources and uses of lipids. Write five differences between Fats and Oils.

OR

What are proteins and peptide bond? How peptide bond is formed in dipeptides and tripeptides ? Write down the range of Number of Amino acids and molecular weights of Proteins. Give importance and sources of proteins.

27. Describe in detail nucleic acids, RNA and DNA. Write down importance of deoxyribonucleic acid (DNA).

28. Describe process of Saponification with the help of flow sheet diagram.

OR 

Describe fractions of petroleum in detail.

29. Justify that electrochemical methods depend upon electrochemical cells.

OR 

What is Titrimetric Analysis? Describe how it is performed with diagram.

30. Explain the process  of preparation sugar from sugar cane.

31. What is Ozone? How does Ozone depletion occurs by Chlorofluorocarbons (CFCs) also mention some adverse impact of it?

OR 

Describe global warming. Justify that green house effect leads to global warming.

32. Describe Gas Chromatography with diagram also write two uses of gas chromatography.

33. What are Soft Water and Hard Water and describe different methods of removing temporary and permanent   hardness. Write down 5 disadvantages of hard water.

34. Definition Water Pollution. Write down its Causes and Effects on Life

35. For the reaction, H2(g) +  I2(g)  2HI(g) (Kc = 57.0); the concentrations of H2(g), I2(g) and HI(g) at time t are:

[H2]t = 0.10 mol dm−3

[I2]t = 0.20 mol dm−3

[HI]t = 0.40 mol dm−3

 Predict in which direction reaction will move to achieve equilibrium.

(Answer; Qc (8.0) is less than Kc (57.0), reaction will move in the forward direction)

OR

Equilibrium occurs when nitrogen monoxide gas reacts with oxygen gas to form nitrogen dioxide gas

              2NO(g)  + O2(g)   2NO2(g)

At equilibrium at 230oC, the concentrations are measured to be

[NO] = 0.0542 mol dm−3

[O2] = 0.127 mol dm−3 

and 

[NO2] = 15.5 mol dm−3

Calculate the equilibrium constant at this temperature. (Book problem 1; page 8)

(Answer; 6.44 x 105 mol-1 dm3)

 

 

 

 

 


1 comment:

  1. Thanks alot for this masterpiece, Sir🤝

    ReplyDelete

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Mid-Term Study Paper XII CHEMISTRY 2025

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