Kerala Syllabus Class 10 Chemistry Model Question Paper Set 2

Practicing Chemistry Class 10 Kerala Syllabus Question Paper Set 2 English Medium helps identify strengths and weaknesses in a subject.

Chemistry Class 10 Kerala Syllabus Model Question Paper Set 2

Time: 1 ½ Hours
Total Score: 40

Instruction:

1. First fifteen minutes are cool off time. Read the questions carefully during this time:
2. Write the answers according to the instructions,
3. Consider the score while writing the answers.
4. Answer only one question for questions having choice.

I. Answer all the questions from 1 to 4. Each question carries 1 score.

Question 1.
Bauxite is the ore of. metal
a) Iron
b) Aluminium
c) Zinc
d) Copper
Answer:
b) Aluminium

Question 2.
Match the following.

Category	Example
(a) Analgesics	i) Paracetamol
(b) Antipyretics	ii) Dettol
(c) Antiseptics	iii) Aspirin

Choose the correct answer from the options given below.
A. (a)-iii, (b)-i, (c)-ii
B. (a)-ii, (b)-i, (c)-iii
C. (a)-i, (b)-ii, (c)-iii
D. (a)-i, (b)-iii, (c)- ii
Answer:
A. (a)-iii, (b)-i, (c)-ii

Question 3.
Which of the following metals reacts vigorously with diluted hydrochloric acid?
a) Gold
b) Magnesium
c) Lead
d) Iron
Answer:
b) Magnesium

Question 4.
Statement 1: Nitrogen, Phosphorous and potassium are the three elements that plants need in large quantities. They are called as primary nutrients.

Statement 2: Elements like Iron and manganese are needed by plants only in very small amounts. They are called micronutrients. Which of the following is correct regarding the above statements?
A. Both statements are correct
B. Both statements are not correct
C. Only statement 1 is correct
D. Only statement 2 is correct
Answer:
A. Both statements are correct

II. Two questions from 5 to 11 have a choice. Each question carries 2 scores. (7 × 2 = 14)

Question 5.
Analyse the structural formulae of the two pairs of compounds given below.
(i) CH₃ – CH₂ – CH = CH₂
(ii) CH₃ – CH = CH – CH₃
a) Write their IUPAC names.
b) What type of isomerism do they exhibit?
Answer:
a) (i) But-l-ene
(ii) But-2-ene

b) Their molecular formulae are the same, but the position of the double bond differs. Hence, they exhibit position isomerism

Question 6.
a) Which of the given polymers is used to coat the inner surface of cookware?
(Polythene, Polyvinyl chloride, Teflon)
b) What is the monomer of this polymer?
Answer:
a) Teflon
b) Tetrafluoroethene (CF₂ = CF₂)

Question 7.
A) Haematite is converted into iron by using the blast furnace.
a) Which substances are fed into the blast furnace along with the ore of iron?
b) Which compound acts as the reducing agent in the blast furnace?
Answer:
a) Limestone, Coke
b) Carbon monoxide (CO)

OR
B) Find the relation and write the answer.
(i) Zinc sulphide : Roasting
Calcium carbonate : ____(a)____

(ii) Magnetite : Magnetic separation
Bauxite : ____ (b) ____
Answer:
a) Calcination
b) Leaching

Question 8.
A few subshells are given. Find the values of n and l.
a) 2s
b) 4p
Answer:
a) n = 2 and l = 0
b) n = 4 and l = 1

Question 9.
448 L of gas is stored in a cylinder at 0°C and 1 atm pressure.
a) How many moles of molecules does this gas contain?
b) What is the number of molecules in this sample?
Answer:
Volume of the gas (V) = 448 L
Temperature (T) = 0 °C
(which is standard temperature)
Pressure (P) = 1 atm
(which is standard pressure)
Number of moles = \(\frac{\text { Volume at STP }}{22.4 \mathrm{~L}}\)
= \(\frac{448 \mathrm{~L}}{22.4 \mathrm{~L}}\)
= 20 moles
Therefore, the gas contains 20 moles of molecules.

b) Number of molecules
= 20 × 6.022 × 10₂₃ molecules.

Question 10.
A galvanic cell is made up of the following half-cells:
• A magnesium electrode immersed in magnesium sulphate solution.
• A nickel electrode immersed in nickel sulphate solution.
The reactions taking place in the half-cells are given.
Mg(s) → Mg²⁺ (aq) + 2e^–
Ni²⁺(aq) + 2e^– → Ni(s)
Draw the cell diagram and label the anode, cathode and direction of flow of electrons.
Answer:

Question 11.
a) Complete the equation of ionisation of phosphoric acid.

b) What will be the basicity of H₃PO₄?
Answer:
a) H₃PO₄ → 3H⁺ + PO₄³
b) Three (3)

OR
B) Certain fertilizers are given.
Urea, sodium nitrate, ammonium phosphate, potassium chloride
Complete the table.

Functions in plants	Fertilisers that can be used
To accelerate plant growth	___(a)___
To increase productivity	Ammonium Phosphate
To boost the immunity of plants	___(b)___

Answer:
a) Urea, Sodium nitrate
b) Potassium chloride

II. Two questions from 12 to 17 have a choice. Each question carries 3 scores. (6 × 3 = 18)

Question 12.
The structural formulae of two familiar compounds are provided below. Analyse them,
i) CH₃ – CH₂ – CH₂ – OH
ii)

a) What is the functional group present in them?
b) Write their IUPAC name.
Compound ___(i)___
Compound ___(ii)___
c) What type of isomerism do they exhibit?
Answer:
a) Hydroxyl (- OH)

b)
(i) Propan-1-ol
(ii) Propan-2-ol

c) Position isomerism.

Question 13.
A) As shown in the galvanic cell of the given figure, place a silver electrode in a solution of silver nitrate and a lead electrode in a solution of lead nitrate. Connect the two electrodes using a copper wire. Also, connect the two beakers using a salt bridge.

a) Where do oxidation and reduction occur?
b) In which direction do electrons flow through the copper wire?
c) Will the cell voltage vary if the two solutions are diluted alternately?
Answer:
a) Anode is where oxidation occurs. The lead (Pb) electrode acts as the anode. The cathode is where reductions occur. The silver (Ag) electrode acts as a cathode.

b) From the lead electrode to the silver electrode

c) Yes, the cell voltage will vary if the solutions are diluted. The cell voltage depends on the concentration of the ions. Diluting the solutions changes the ion concentrations, which affects the electrode potential and thus alters the overall cell voltage.

OR
B) a) Which is the anode and cathode in the Mg – Ag galvanic cell?
b) Write the reaction taking place at the anode and cathode of this cell.
c) Write the equation of a redox reaction.
Answer:
a) Anode – Mg, Cathode – Ag
b) Anodic reaction: Mg → Mg²⁺ + 2e^–
Cathodic reaction: 2Ag + 2e → 2Ag
c) Redox reaction: Mg + 2Ag⁺ → Mg⁺ + 2Ag

Question 14.
Choose the correct answer from the box.
Ethanoic acid, Sodium hydroxide, Methanol, Glycerol, 95.6% Ethanol
a) Which alcohol is known as the wood spirit?
b) Which substance is known as rectified spirit?
c) Name the acid present in vinegar?
Answer:
a) Methanol
b) 95.6% ethanol
c) Ethanoic acid

Question 15.
The element Cu, with atomic number 29, undergoes a chemical reaction to form an ion with an oxidation state of +2.
a) Write the subshell electron configuration of this ion.
b) Is it possible for this element to exhibit a different oxidation state? Why?
c) Write the chemical formula of a compound formed when this element reacts with chlorine.
Answer:
a) ls² 2s²2p⁶3s²3p⁶4s²3d⁹

b) Yes. Being a d-block element, there is only a very small difference in the energy levels of electrons in 4s and 3d. This allows for the loss of electrons from the 4s and 3d orbitals, resulting in variable oxidation states.

c) CuCl₂

Question 16.
A) Zinc is an industrially important metal
a) Which is the ore of Zinc?
b) Write the name of the concentration method used for Zinc ore?
c) What is the process used in the conversion of zinc ore to zinc oxide after the concentration of the ore?
Answer:
a) Zinc blende (ZnS)
b) Froth floatation
c) Roasting

OR
B) Alloys containing iron are given. Find a, b, c

Alloys	Constituent elements	Uses
Alnico	___(a)___	For the manufacture of permanent magnets
___(b)___	Fe, Cr, Ni, C	Resist the corrosion of iron. Making of utensils.
Silicon steel	___(c)___	Used in the core of electromagnetic instruments like motors, generators, transformers etc.

Answer:
a) Fe, Al, Ni, Co
b) Stainless steel
c) Fe, Si, C

Question 17.
Find the samples with equal volumes from the ones given below at STP.
a) 64g O₂
b) 44g CO₂
c) 2 × 6.022 × 10²³ NH₃ molecules SO₄
Answer:–
a) 64g O₂
No of moles = \(\frac{\text { Mass }}{\text { Molar mass }}=\frac{64}{32}\) = 2 mole
Volume of Oxygen = No of moles × 22.4L = 2 × 22.4L = 44.8L

b) 44g CO₂
No of moles = \(\frac{\text { Mass }}{\text { Molar mass }}=\frac{44}{44}\) = 1 mole
Volume of 1 mole CO₂ = No of moles × 22.4L = 1 × 22.4L = 22.4L

c) 2 × 6.022 × 10²³ NH3 molecules No of moles = 2
Volume at STP = No of moles × 22.4L = 2 × 22.4L = 44.8L Therefore,
(a) and (c) have equal volume.

Question 18 has a choice. It carries 4 scores. (1 × 4 = 4)

Question 18.
A) A reversible reaction at equilibrium is given.

a) Write the equation of the forward reaction.
b) How do the following changes affect the rate of forward reaction?
i. Adding more oxygen.
ii. Increasing pressure
c) What is the effect of a catalyst in a reversible reaction at equilibrium?
d) How does an increase in the concentration of NO (Nitric oxide) influence the rate of the forward reaction?
Answer:
a) 2NO(g) + O₂(g) → 2NO₂(g)
b)
i. Increases
ii. Increases
c) Catalyst does not affect reversible reactions at equilibrium.
d) Amount of product decreases.

OR
B)
a) The industrial preparation of sulphuric acid is known as _____.
b) Which is the catalyst used in this process?
c) Take some sugar in a watch glass and add a few drops of concentrated sulphuric acid into it. What is your observation? Which chemical property of sulphuric acid is shown here?
d) Why is concentrated sulphuric acid not used as a drying agent in the preparation of Ammonia?
Answer:
a) Contact process
b) Vanadium pentoxide (V₂O₅)
c) Sugar is converted into a black substance. The dehydrating nature of sulphuric acid is shown here.
d) Concentrated sulphuric acid is not used as a drying agent in the preparation of ammonia because ammonia is basic and can react with concentrated Sulphuric acid, and then it will form ammonium sulphate.