Assertion & Reason Test: The p-Block Elements


15 Questions MCQ Test Chemistry Class 12 | Assertion & Reason Test: The p-Block Elements


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Attempt Assertion & Reason Test: The p-Block Elements | 15 questions in 30 minutes | Mock test for NEET preparation | Free important questions MCQ to study Chemistry Class 12 for NEET Exam | Download free PDF with solutions
QUESTION: 1

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): N2 is less reactive than P4
Reason (R): Nitrogen has more electron gain enthalpy than phosphorus.

Solution:

Due to high bond dissociation energy of triple bond between the two N atoms, nitrogen (N) is less reactive than P4 and its electron gain enthalpy is less than phosphorus.

QUESTION: 2

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): Bismuth forms only one well characterised compound in +5 oxidation state.
Reason (R): Elements of group-15 form compounds in +5 oxidation state.

Solution:

Elements of group-15 form compounds in +5 oxidation state. Bismuth forms only one well characterised compound in +5 oxidation state which is BiF5. Due to inert pair effect bismuth exhibit +3 oxidation state and only forms trihalides. But due to small size and high electronegativity of fluorine, Bismuth forms BiF5.

QUESTION: 3

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): Both rhombic and monoclinic sulphur exist as S8 but oxygen exists as O2.
Reason (R): Oxygen forms pp-pp multiple bond due to small size and small bond length but pπ-pπ bonding is not possible in sulphur.

Solution:

Sulphur (S) exists as S8 but oxygen forms pπ-pπ multiple bonds which is not present in S.

QUESTION: 4

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): SF6 cannot be hydrolysed but SF4 can be.
Reason (R): Six atoms in SF6 prevent the attack of H2O on sulphur atom of SF6.

Solution:

SF6 is sterically protected due to presence of six F atoms around S atom which prevents the attack of H2O on SF6.

QUESTION: 5

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): HI cannot be prepared by the reaction of KI with concentrated H2SO4.
Reason (R): HI has lowest H–X bond strength among halogen acids.

Solution:

Both statements are correct but are independent of each other. HI cannot be prepared by the reaction of KI with concentrated H2SO4 as it results in the formation of HI which further oxidizes to I2 as H2SO4 is a strong oxidizing agent.

QUESTION: 6

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): F2 has lower bond dissociation energy than Cl2.
Reason (R): Fluorine is more electronegative than chlorine.

Solution:

F2 has higher bond dissociation enthalpy than Cl2.

QUESTION: 7

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion(A): Group 18 gases exhibit very high ionisation enthalpy.
Reason (R): They have a stable electronic configuration.

Solution:

Group 18 gases exhibit very high ionisation enthalpy because they have a stable electronic configuration.

QUESTION: 8

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion(A): Helium diffuses through most commonly used laboratory materials.
Reason(R): This gas has a very low melting  point.

Solution:

Helium diffuses through most commonly used laboratory materials which is an unusual property of this gas.

QUESTION: 9

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): HNO3 makes iron passive.
Reason (R): HNO3 forms a protective layer of ferric nitrate on the surface of iron.

Solution:

HNO3 makes iron passive and its passivity is attained by formation of a thin film of oxide on iron.

QUESTION: 10

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): NaCl reacts with concentrated H2SO4 to give colourless fumes with pungent smell. But on adding MnO2 the fumes become greenish yellow. 
Reason (R): MnO2 oxidises HCl to chlorine gas which is greenish yellow.

Solution:

Colourless fumes of hydrochloric acid (HCl) become greenish yellow because MnO2 oxidises HCl to chlorine gas.

QUESTION: 11

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): NaCl reacts with concentrated H2SO4 to give colourless fumes with pungent smell. But on adding MnO2 the fumes become greenish yellow.
Reason (R): MnO2 oxidises HCl to chlorine gas which is greenish yellow

Solution:

Colourless fumes of hydrochloric acid(HCl) because greenish yellow because MnO2 oxidises HCl to chlorine gas.

QUESTION: 12

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): H2O a liquid and H2S a gas.
Reason (R): Water molecules are held by H-bonds while in H2S molecules no such interactions are present between molecules.

Solution:

Due to small size and high electronegativity of oxygen, water is highly associated with intermolecular hydrogen bonding but molecules of H2S are held together by van der Waal’s forces of attraction. Hence, H2O is a liquid and H2S is a gas.

QUESTION: 13

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): F2 is a strong oxidizing agent.
Reason (R): Electron gain enthalpy of fluorine is less negative.

Solution:

Fluorine is the best oxidising agent because it has more reduction potential (more ability to lose the electrons) which is attributed to its high electronegativity.

QUESTION: 14

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion (A): F2 has lower reactivity.
Reason (R): F-F bond has low Δbond Ho.

Solution:

Fluorine is the maximum reactive because of low bond dissociation enthalpy.

QUESTION: 15

Directions: In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as.

Assertion(A): The noble gases are inactive.
Reason(R): These gases have a closed shell  structure.

Solution:

The noble gases are inactive as they have a closed shell structure.

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