IX 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)

Q1.   Define any three of the following:

Valency, Electronegativity, electron affinity, Tyndall effect, free radical, molecular ion, mole, molar volume,      empirical and molecular formula, Molarity, concentration, false solution, mass/volume percent, Freezing Point,    absolute zero, allotropy, Dobereiner’s law of Triads, Newland’s law of Octaves, Mendeleev’s Periodic law, Periodicity, periodic trend, modern, periodic law

 

Q2.   Write down three differences between any one of the following:

(i)   Alkali metal and halogens                      

(ii) Ionic, covalent bond and dative bond

(iii) elements, compounds and mixtures   

(iv) Ionic compounds and covalent compounds

(v) Solution, suspension and Colloid          

(vi) metal, metals and metalloids

(vii) Atom and molecule and ion                 

(viii) Molecule and molecular ion and free radical

 

Q3.   What is meant by atomic number and mass number. Define and give uses of isotopes. Discuss the isotopes of Hydrogen or carbon or uranium. Mention the number of electrons, protons and neutrons in following atoms: 

OR

Differentiate between EF and MF. Describe relationship between empirical and molecular formula? Find out      molecular formula of a compound if its empirical formula is CH₂O and molecular mass 60 amu. Complete the    following chart:

Q4.   Identify group and period in the periodic table of the following elements

(i) ₃Li or ₈O or ₁₅P 

(ii) ₉F or ₁₁Na and ₁₇Cl   

(iii) ₁₂Mg or ₁₃ Al or ₁₄Si

OR

An element has 7 (or 1 or 2 or 8) electrons in its M-shell. Answer the following questions:

(i)    Determine its atomic number and give its Electronic configuration.

(ii)   Identify the group, period and block of given element.

(iii) Write down three characteristics of the belonging group. Also Write down the name and symbol of radioactive element of this group.

Q5.   Compare of reactivity of Alkali and Alkaline Earth Metals

OR 

Write down one contribution of any 10 scientists in the field of chemistry. OR write down three significant reasons to study chemistry. 

OR 

Explain the importance of glues and epoxy resins in our society.

        

Q6.   Write chemical formulae of any three of the following compounds:

Sand (SiO₂), Limestone (CaCO₃) ,Sodium nitrate (NaNO₃), table salt (NaCl), sal ammoniac (NH₄Cl), Caustic soda (NaOH), caustic potash (KOH), washing soda (Na₂CO₃.10H₂O), baking soda (NaHCO₃), soda ash (Na₂CO₃), Epsom            salt (MgSO₄.7H₂O),gypsum (CaSO₄.2H₂O), oleum (H₂S₂O₇), marsh gas (CH₄), blue vitriol (CuSO₄.5H₂O), sugar (C₁₂H₂₂O₁₁), ethyl alcohol, Acetylene, Ethylene,.

OR

What is coordinate covalent bond? Explain with two examples.

 

Q7.   Write down any three points of atomic model proposed by Schrodinger or Bohr.

Or

Describe wave particle duality of electron of De Broglie Hypothesis? Prove that modern theory of De Broglie is related with Einstein and Plank's equations.

 

Q8.   Write down electronic configuration of ₅B, ₉F, ₇N, ₁₁Na, ₁₅P, ₂₀Ca, ₁₉K⁺, ₈O²⁻, ₁₆S²⁻, ₁₂Mg²⁺, ₁₇Cl⁻.

OR

Justify that Rutherford atomic model has defects? What are Limitations of Bohr's Atomic Model?

 

Q9.  Balance the any three of the following chemical equations:

             2KClO₃             → 2KCl      + 3O₂

             2Ba(NO₃)₂      →  2BaO  + 4NO₂  +  O₂

             2Na   + 2H₂O → 2NaOH + H₂

             2NH₃ + 3Cl₂  →  N₂ + 6HCl

             MnO₂ + 4HCl  → MnCl₂ + 2H₂O + Cl₂

             4NH₃  + 5O₂   → 4NO       +  6H₂O

4Zn + 10HNO₃  → 3H₂O+ NH₄NO₃    + 4Zn(NO₃)₂

3CuO      + 2NH₃ → 3Cu  +  N₂ + 3H₂O

OR

How is electronegative value determined the formation of chemical bond? Describe ionic character in covalent       bond.

 

Q10.    What is KMT? Give its main postulates with respect to three states of matter.

OR

What is diffusion and Graham’s law of diffusion of gases? Which gas from among CO₂, CH₄ and NH₃ will diffuse the fastest and why? Give the reason.

 

Q11.    Differentiate between amorphous and Crystalline Solids?

OR

Explain the solute-solvent interaction to prepare sodium chloride solution.

 

Q12.Define electrochemical reaction. Write down 2 differences between oxidation and reduction and oxidizing agent and reducing agent with examples. Identify oxidizing and reducing agents of the following chemical reaction:

              Zn + Cl₂ → ZnCl₂

OR

Differentiate between electrolytes and non-electrolytes with examples. Identify strong and weak electrolytes from the following:

HCl (S), KI (S), NaOH (S), H₂S (W), CH₃COOH (W), NH₄OH (W), NaCl (S), C₂H₅OH (W)

 

Q13. What is corrosion of metal and rusting? Name the methods which are used to protect metal from corrosion. How cathodic protection prevent metal from corrosion?

OR

Write down the composition of following alloys:

Brass (Cu-Zn,[4:1]), Bronze (Cu-Sn-Zn) [9:1], Bell metal (Cu-Sn), Monel (Ni-Cu-Fe), Amalgam (Hg-Ag-Cu-Zn), Pewter (Sn-Cu-Pb-Sb-Bi), White gold (Au-Pb-Ag-Cu (18 karat), Duralumin (Al-Cu-Mg-Ni)

 

Q14. What are metalloids? Write names and symbols of any 5 metalloids.

OR

Write names and symbols of some noble metals. Explain inertness of noble metals.

OR

Define Moh Scale. What are Soft & Hard Metals? Differentiate between sodium and iron as soft and hard metal.

 

Q15. What is the boiling point? How boiling point is affected by different factors? How boiling point of a substance is affected by atmospheric pressure?

            

Q16.    What is density, how the density of liquid is affected by temperature and pressure?

OR

What is plasma? Explain plasma with the daily life examples?

 

Q17. Describe the construction of electrochemical cell. Write down names of two types of electrochemical cells.   Write down 4 applications of electrolytic cells or electrolysis.

 

Q18.    Give reason:

(i) Why gasoline does not dissolve in water?

(ii) Alkali metals are not found in free state in nature, why?

(iii) Why ionic compounds conduct electricity in molten or in aqueous solutions only?

(iv) Why the solubility of a salt increases with the increase in temperature?

(v) Explain why table salt has a very high melting point.

(vi) Atomic radii increases down a group and decrease across a period.

(vii) Alkali metals have the largest while halogens have the smallest atomic radii in their period.

(viii) Shielding effect of inner electrons remains the same across a period.

 (ix) Ionization energy, electron affinity and electronegativity show same trends across a period.

(x) Covalent bonds are strong and hard to break but why most of the covalent compounds have low melting and boiling points. 

19.   Discuss Rutherford’s Alpha particles scattering experiment & write down the postulates of his atomic model.

         OR

Determine the demarcation of periodic table in to s, p, d and f blocks.

 

20.   Define ionic bond. Discuss the formation of sodium chloride (NaCl).

         OR

What is meant by covalent bond and coordinate covalent bond? Describe the formation of a covalent bond        between two nonmetallic atoms. Explain single, double and triple covalent bond with examples. Explain dative bond with two examples.

 

21.   Describe the Boyle's law or Charle’s law with example.

         OR

Define vapour pressure. How equilibrium state involved in vapour pressure of liquids in close system? Describe   the factors which affect on vapour pressure

 

22.   Define the term solubility. How does nature of solute and solvent determine the extent of dissolution? Why the solubility of a salt increases with the increase in temperature?

OR

Discuss discharge tube experiment for the discovery of electrons with 4 properties of cathode rays.

 

23.   State and explain Faraday’s Laws of electrolysis.

         OR

What is electroplating? How steel object can be electroplated with zinc and silver?

 

25.   Explain electronegative character of non-metals or electropositive character of metals. Discuss the reactivity of    Halogens

         OR

What are transition elements? Give their types. Give their 4 general properties.

 

26.   Explain the experiment to test CO₃^2‒, Cl^‒ and I^‒ ions and Zn²⁺, Mg²⁺, Ca²⁺ and Ba²⁺ ions.

 

Numericals

25.   Calculate the number of moles, number of molecules present in 8g of C₆H₁₂O₆? 

(answer; 0.04, 2.40 x 10²² molecules)

OR

Calculate the number of moles, number of molecules and number of atoms present in 10 g of H₂SO₄

 (answer; 0.10 mole, 6.02 x 1010²², 4.214 x 10²³ atoms)

 

26.   What is the mass of oxalic acid (C₂H₂O₄) required to prepare 100 cm³ volume of 2M oxalic acid solution?

         Or

What is the molarity of the solution prepared by dissolving 1.25 g of HCl gas into enough water to make 30 cm³ of solution?

 

27.   Determine the percentage concentration of the solution obtained by dissolving 10g sugar in 140g water

OR

A solution of 20 cm³ of alcohol is dissolved in 80cm³ of water. Calculate the concentration (v/v) of solution.

 

28.   10M HNO₃ solution is available in laboratory. How would you prepare 500 cm³ of 0.1M solution?

OR

A sample of sulphuric acid has the molarity 20M. How many cm³ of solution should you use to prepare 500 cm³ of 0.5M H₂SO₄? (Answer; 12.5cm³)

 

29.   The 800 cm³ of a gas is enclosed in a container under a pressure of 750 mm. If the volume is reduced to 250     cm³, what will be the pressure?

         OR

A sample of Hydrogen gas has a volume of 350 cm³ at 40 C. If gas is allowed to expand up to 700 cm³ at constant pressure. Find out its final temperature? (answer; 626 K)