Kerala SSLC Chemistry Board Model Paper March 2022 with Answers English Medium

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Kerala Syllabus Class 10 Chemistry Board Model Paper March 2022 with Answers English Medium

Time: 1½ Hours
Total Score: 40

Instructions:

• There is a ‘Cool-off time’ of 15 minutes in addition to the writing time.
• Use this time to get familiar with questions and to plan your answer.
• Questions with different scores are given as distinct parts.
• Read the instructions carefully before answering the questions.
• Keep in mind, the score and time while answering the questions.
• The maximum score for questions from 1 to 24 will be 40.

Part – I
Questions from 1 to 9 carry 1 score each

A. Answer any 4 questions from 1 to 6. (4 × 1 = 4)

Question 1.
Which Subshell is common to all shells?
Answer:
s-subshell

Question 2.
The number of molecules present in 1 GMM N₂ is _____________
Answer:
6.022 × 10²³ or Avagadro number or N_A

Question 3.
Which one of the following metals reacts with hot water?
[Au, Cu, Ag, Mg]
Answer:
Mg

Question 4.
Fill up suitably:
OH: Hydroxyl Group
-COOH: _____________
Answer:
-COOH: Carboxylic Group

Question 5.
Complete the given chemical equation.
NH₄Cl → _____________ + HCl
Answer:
NH₄Cl → NH₃ + HCl

Question 6.
Which is the method used to concentrate Sulphide ores?
Answer:
Froth Floatation

B. Answer all questions from 7 to 9. (3 × 1 = 3)

Question 7.
In f-block elements, the last electron is filled in _____________ subshell.
Answer:
Inner Penultimate ‘f’ subshell

Question 8.
Which substance is deposited at the Cathode, when molten Sodium Chloride is electrolysed?
[Oxygen, Chlorine, Sodium, Hydrogen]
Answer:
Sodium

Question 9.
In electrolytes, _____________ are responsible for the conduction of electricity.
Answer:
Charged Ions

Part – II
Questions from 10 to 12 carry 2 scores each

A. Answer the following question. (1 × 2 = 2)

Question 10.
(a) Which of the following chemicals are used to prepare ammonia (NH₃) in the laboratory? (1)
[NaCl, Ca(OH)₂, CaCl₂, NH₄Cl]
(b) Ammonia gas produced is passed through quick lime. Give reason. (1)
Answer:
(a) Ca(OH)₂, NH₄Cl
(b) To remove moisture.
Quick lime is a good drying agent.

B. Answer any one question from 11 to 12. (1 × 2 = 2)

Question 11.
The volume of 1 mole of any gas at STP is 22.4 L. What will be the volume of 34 g NH₃ at STP? (2)
[1 GMM NH₃ = 17 g]
Answer:
No. of moles in STP = \(\frac{\text { Given mass }}{\text { GMM }}=\frac{34}{17}\) = 2 moles
Volume of 2 moles = 2 × 22.4 = 44.8 L

Question 12.
Copper is electroplated on an iron ring.
(a) Which electrolyte is used here? (1)
(b) Which metal is connected to the positive terminal of the battery? (1)
Answer:
(a) Copper Sulphate (CuSO₄) Solution
(b) Pure Copper

Part – III
Questions from 13 to 17 carry 3 scores each

A. Answer any three questions from 13 to 16. (3 × 3 = 9)

Question 13.
Match columns A, B, and C suitably: (3)

A. Alloy Steel	B. Property	C. Use
Stainless Steel	High Resistance	For the manufacture of permanent magnets
Nichrome	Magnetic Nature	For the manufacture of utensils
Alnico	Hard	For making heating coils

Answer:

A. Alloy Steel	B. Property	C. Use
Stainless Steel	Hard	For the manufacture of utensils
Nichrome	High Resistance	For making heating coils
Alnico	Magnetic Nature	For the manufacture of permanent magnets

Question 14.
In element A (symbol is not real), the last two electrons are added to the 4s subshell.
(a) Write down the subshell electronic configuration of A. (1)
(b) Which period does it belong to? (1)
(c) Find its group number. (1)
Answer:
(a) 1s², 2s², 2p⁶, 3s², 3p⁶, 4s²
(b) 4th Period
(c) 2nd Group

Question 15.
N₂ (g) + 3H₂ (g) \(\rightleftharpoons\) 2NH₃ (g) + Heat
How do the following changes affect the rate of forward reaction in the given system at equilibrium?
(a) Pressure is decreased. (1)
(b) Temperature is increased. (1)
(c) More H₂ is added. (1)
Answer:
(a) The rate of forward reaction will be decreased. Because due to forward reaction number of molecules decreases.
(b) The rate of forward reaction decreases. Because the forward reaction is exothermic.
(c) Rate of forward reaction increases. Because the concentration of reactant increases.

Question 16.
Choose the name of the reaction from the given box and complete the table.

Substitution Reaction, Thermal Cracking, Addition Reaction, Combustion, Polymerisation

Chemical Equation	Name of Reaction
CH2 = CH2 + H2 → CH3 – CH3	_________________________
CH4 + 2O2 → CO2 + 2H2O	_________________________
CH3 – CH3 + Cl2 → CH3 – CH2 – Cl + HCl	_________________________

Answer:

Chemical Equation	Name of Reaction
CH2 = CH2 + H2 → CH3 – CH3	Addition Reaction
CH4 + 2O2 → CO2 + 2H2O	Combustion
CH3 – CH3 + Cl2 → CH3 – CH2 – Cl + HCl	Substitution Reaction

B. Answer the following question. (1 × 3 = 3)

Question 17.
Examine the following compounds and answer the questions.
(i) CH₃ – O – CH₃
(ii) CH₃ – CH₂ – CH₂ – OH

(iv) CH₃ – CH₂ – OH
(a) Find out the isomeric pairs. (2)
(b) Which is the functional group of CH₃ – O – CH₃? (1)
Answer:

(b) -O- (Alkoxy Group)

Part – IV
Questions from 18 to 22 carry 4 scores each

A. Answer any two questions from 18 to 20. (2 × 4 = 8)

Question 18.
The relation between pressure and volume of a fixed mass of gas at constant temperature is given in the table.

Pressure (P) Atm	Volume (V) L	P × V
1	200	200
2	(a)	200
(b)	50	(c)

(a) Find the values of a, b and c. (3)
(b) Which gas law is applied here? (1)
Answer:
(a) a = 100 L
b = 4 atm
c = 200
(b) Boyle’s Law

Question 19.
The structural formula of a hydrocarbon is given:

(a) Write the molecular formula of the given hydrocarbon. (1)
(b) How many carbon atoms are there in the longest carbon chain? (1)
(c) Name the branch present. (1)
(d) Write its IUPAC name. (1)
Answer:
(a) C₇H₁₆
(b) 6
(c) Methyl
(d) 3-Methyl Hexane

Question 20.
The following chemical equations represent the reactions taking place in the blast furnace during the manufacture of iron.

• C + O₂ → CO₂ + Heat
• CO₂ + C + Heat → 2CO
• Fe₂O₃ + 3CO → 2Fe + 3CO₂
• CaCO₃ → CaO + CO₂
• CaO + SiO₂ → CaSiO₃

(a) Which is the ore of iron used in the blast furnace? (1)
(b) Which substance acts as the reducing agent in this process? (1)
(c) What is the role of CaO in this process? (1)
(d) Which one of the given chemical equations represents slag formation? (1)
Answer:
(a) Fe₂O₃ or Haematite
(b) CO or Carbon Monoxide
(c) Used as Flux to remove the impurity in the iron ore.
(d) CaO + SiO₂ → CaSiO₃

B. Answer any one question from 21 to 22. (1 × 4 = 4)

Question 21.
Choose the correct answer from the box.

Ethanoic Acid, Sodium Hydroxide, Methanol, Glycerol, 95.6% Ethanol

(a) Which alcohol is known as wood spirit? (1)
(b) Which substance is known as rectified spirit? (1)
(c) Name the acid present in vinegar. (1)
(d) Which is the by-product in the manufacture of soap? (1)
Answer:
(a) Methanol
(b) 95.6% Ethanol
(c) Ethanoic Acid
(d) Glycerol

Question 22.
A few drops of concentrated sulphuric acid are added to sugar.
(a) What do you observe? (1)
(b) Which property of concentrated sulphuric acid is shown here? (1)
(c) Why concentrated sulphuric acid is not used as a drying agent in the preparation of ammonia? (1)
(d) Which substance is used to identify sulphate salts? (1)
(NaCl, KCl, BaCl₂, BaSO₄)
Answer:
(a) Sugar gets charred to carbon. CO₂ gas and water vapour are liberated.
(b) Dehydrating Property.
(c) Concentrated sulphuric acid reacts with basic ammonia and forms ammonium sulphate salt.
(d) BaCl₂

Part – V
Questions from 23 to 24 carry 5 scores each

A. Answer any one question from 23 to 24. (1 × 5 = 5)

Question 23.
The atomic number of an element X is 13. (Symbol is not real)
(a) Write down the subshell electronic configuration of element X. (1)
(b) Write down its subshell electronic configuration using the symbol of the preceding noble gas. (1)
(c) Which block does it belong to? (1)
(d) Find the total number of electrons in all the p subshells of this element. (1)
(e) Write down the subshell electronic configuration of the X3+ ion. (1)
Answer:
(a) X₁₃ = 1s², 2s², 2p⁶, 3s², 3p¹
(b) [Ne] = 3s² 3p¹
(c) P-Block
(d) 7
(e) X³⁺ = 1s², 2s², 2p⁶

Question 24.
The diagram of a galvanic cell is given.

[Hint: Order of Reactivity Mg > Zn > Fe > Cu > Ag]
(a) What is the energy change taking place in a galvanic cell? (1)
(b) At which electrode does oxidation take place? (1)
(c) Which metal does act as the cathode? (1)
(d) If Silver and Copper are used as electrodes to construct the cell, which metal acts as the anode? (1)
(e) Write down the chemical equation of the reaction taking place at the Copper electrode in this case. (1)
Answer:
(a) Chemical Energy → Electrical Energy
(b) Anode (Zn rod)
(c) Cu
(d) Copper
(e) Cu → Cu²⁺ + 2e^– (Oxidation)