Chemical Reactions

01

PYQ 2022

medium

chemistry ID: ap-eapce

Identify A and B from the following reaction:\ NaNO3(\xrightarrow{\Delta}\) xA + yB

1

NaNO2, O2

2

Na2O, NO2

3

Na2O, NO

4

Na, NO2

02

PYQ 2022

medium

chemistry ID: ap-eapce

For the formation of NH (g) from its constituent elements, which of the relation between the reaction quotient (Q) and equilibrium constant (K) is correct for the backward reaction?

1

Q = K

2

Q>K

3

Q

4

Q = K = 1

03

PYQ 2022

medium

chemistry ID: ap-eapce

Among P, S and N, the elements which undergo disproportionation when heated with NaOH solution

1

P, S only

2

N, S only

3

N, P only

4

P, N, S

04

PYQ 2022

medium

chemistry ID: ap-eapce

Match the following List - I (Type of reaction) \quad List - II (unbalanced equation) A Combination reaction \quad i) AgNO + CaCl AgCl + Ca(NO ) B Decomposition reaction \quad ii) Cl Cl + ClO C Disproportionation reaction \quad iii) Mg + N Mg N D Displacement reaction \quad iv) KClO KCl + O }

1

$A-(iii); B-(ii); C-(iv); D-(i) % Note: Image shows this as 1.$

2

$A-(i); B-(iv); C-(ii); D-(iii) % Note: Image shows this as 2.$

3

$A-(i); B-(ii); C-(iii); D-(iv) % Note: Image shows this as 3.$

4

$A-(iii); B-(iv); C-(ii); D-(i) % Note: Image shows this as 4. and marked correct.$

Official Solution

Correct Option: (4)

$Let's analyze each reaction in List - II and match it with the type of reaction in List - I. Reaction i) AgNO + CaCl AgCl + Ca(NO) This is a double displacement reaction (also called metathesis). Two ionic compounds exchange ions to form two new compounds. Specifically, AgCl often precipitates. This is a type of displacement reaction where ions are displaced. Balanced: . This matches D Displacement reaction . So, D-(i). Reaction ii) Cl Cl + ClO In this reaction, elemental chlorine (Cl, oxidation state 0) is converted into chloride ion (Cl, oxidation state -1) and chlorate ion (ClO, oxidation state of Cl is +5). Chlorine is simultaneously oxidized (0 to +5) and reduced (0 to -1). This is a disproportionation reaction. This reaction usually occurs in basic medium: . This matches C Disproportionation reaction . So, C-(ii). Reaction iii) Mg + N Mg N Two elements, magnesium (Mg) and nitrogen (N), combine to form a single compound, magnesium nitride (Mg N). This is a combination reaction (also called synthesis reaction). Balanced: . This matches A Combination reaction . So, A-(iii). Reaction iv) KClO KCl + O} A single compound, potassium chlorate (KClO), breaks down into simpler substances, potassium chloride (KCl) and oxygen (O), upon heating. This is a decomposition reaction. Balanced: . This matches B Decomposition reaction . So, B-(iv). Summarizing the matches: A - (iii) B - (iv) C - (ii) D - (i) This set of matches corresponds to option (d).$

05

PYQ 2023

medium

chemistry ID: ap-eapce

$Identify the reaction in which oxygen is not one of the products.$

1

2

3

4

Official Solution

Correct Option: (4)

$To identify the reaction where oxygen is not one of the products, we analyze each option: - produces products containing oxygen. - produces products where oxygen is not involved. - is a reaction that produces oxygen. - again produces oxygen in the products. Thus, the correct reaction where oxygen is not one of the products is option (4).$

06

PYQ 2025

medium

chemistry ID: ap-eapce

$Consider the following: Statement I: CCl 4 does not undergo hydrolysis. But SiCl 4 undergoes hydrolysis. Statement II: Thermal and chemical stability of GeX 4 is more than GeX 2 .$

1

$Both statement-I and statement-II$

2

$Both statement-I and statement-II$

3

$Statement-I is correct, but statement-II$

4

$Statement-I is not correct, but statement-II$

Official Solution

Correct Option: (1)

$Explanation for Statement-I: CCl 4 lacks vacant d-orbitals to accept electrons from water, so no hydrolysis. SiCl 4 has vacant 3d orbitals and undergoes hydrolysis easily. Explanation for Statement-II: GeX 4 (Group 14 element, higher oxidation state) is more stable due to inert pair effect stability trend.$

07

PYQ 2025

hard

chemistry ID: ap-eapce

$How many grams of calcium carbonate ( ) are required to completely neutralize 200 mL of 0.5 M HCl? Given the reaction: $ \mathrm{CaCO}_3 = 100 \, \text{g/mol}$)$

1

$5.0 g$

2

$10.0 g$

3

$2.5 g$

4

$7.5 g$

Official Solution

Correct Option: (1)

$Given: Step 1: Calculate Moles of HCl Moles of HCl = Molarity Volume (in liters): Step 2: Use Stoichiometry From the reaction, 1 mole of neutralizes 2 moles of HCl. Thus, moles of required: Step 3: Calculate Mass of Mass = Moles Molar mass: Thus, the mass required is:$

08

PYQ 2025

easy

chemistry ID: ap-eapce

$A current of 2 A is passed through molten CaCl for 1930 seconds. What is the mass of calcium deposited at the cathode? (Ca molar mass = 40 g/mol, valency = 2, Faraday's constant = 96500 C/mol)$

1

$0.4 g$

2

$0.8 g$

3

$1.29 g$

4

$1.5 g$

Official Solution

Correct Option: (2)

$The amount of substance deposited at the cathode is given by the formula: where: - (current) - (time) - (molar mass of calcium) - (valency of calcium) - (Faraday's constant) Substituting the values: Final answer Answer:$

09

PYQ 2025

medium

chemistry ID: ap-eapce

$For a reaction: It is found that doubling the concentration of A doubles the rate, while doubling B increases the rate fourfold. What is the overall order of the reaction?$

1

$1$

2

$2$

3

$3$

4

$4$

Official Solution

Correct Option: (3)

$The rate law for the reaction can be written as: where: - is the order of the reaction with respect to, - is the order of the reaction with respect to, - is the rate constant. Doubling the concentration of A: - When the concentration of is doubled, the rate doubles. This implies that because: Doubling the concentration of B: - When the concentration of is doubled, the rate increases fourfold. This implies that because: Thus, the overall order of the reaction is . Final answer Answer:$

10

PYQ 2025

medium

chemistry ID: ap-eapce

$Which of the following compounds undergoes Markovnikov addition when treated with HBr?$

1

$CH2=CH2$

2

$CH3-CH=CH2$

3

$CH3-C=CH$

4

$CH-CH2$

Official Solution

Correct Option: (2)

$Markovnikov's rule states that when HX is added to an alkene, the hydrogen atom attaches to the carbon atom that already has the greater number of hydrogen atoms (the more substituted carbon atom). In the compound, the hydrogen from HBr will add to the carbon atom in the double bond that has more hydrogen atoms (the CH2 group), and the bromine will add to the more substituted carbon (the CH3 group). Thus, the compound that follows Markovnikov's rule is . Final answer Answer:$

11

PYQ 2025

medium

chemistry ID: ap-eapce

$The combustion of methane is represented by the equation: Given: What is the enthalpy change () for the combustion of 1 mole of methane?$

1

$-890.1 kJ/mol$

2

$-650.1 kJ/mol$

3

$-1000.5 kJ/mol$

4

$-500.0 kJ/mol$

Official Solution

Correct Option: (1)

$To determine the enthalpy change () for the combustion of 1 mole of methane, we must use the enthalpies of formation for the reactants and products. The overall reaction is: Using the formula for enthalpy change: Given values: The reaction includes 1 mole of and 2 moles of as products. Total : Since oxygen is in elemental form, its standard enthalpy of formation is 0: Now, calculate : Therefore, the enthalpy change for the combustion of 1 mole of methane is: -890.3 kJ/mol$

12

PYQ 2025

medium

chemistry ID: ap-eapce

$Which of the following statements is true about an exothermic reaction?$

1

$is positive and heat is absorbed from the surroundings.$

2

$is negative and the temperature of the surroundings increases.$

3

$is zero and no energy change occurs.$

4

$is negative but the reaction is always non-spontaneous.$

Official Solution

Correct Option: (2)

$- An exothermic reaction releases heat to the surroundings. - Therefore, the enthalpy change is negative because the system loses heat, making (B) correct. - The heat released increases the temperature of the surroundings. - (A) is incorrect because a positive means heat is absorbed (endothermic). - (C) is incorrect because exothermic reactions involve a change in energy. - (D) is incorrect because negative often correlates with spontaneous reactions, not always non-spontaneous. Answer:$

High-Yield Trend

Chapter Questions
12 MCQs

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Chemical Reactions

High-Yield Trend

Chapter Questions 12 MCQs

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Chapter Questions
12 MCQs