Assertion and Reason Questions for Class 11 Chemistry Chapter 11 The p-Block Elements
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Q.1. Assertion : In carbon dioxide, the carbon is sp3 hybridized.
Reason : CO is a linear monomeric covalent compound.
AnswerAnswer:(d) : In CO2, C is sp hybridized. It forms two s bonds with two oxygen atoms and two pp-pp multiple bonds. So CO2 is a linear, monomeric and covalent compound.
Q.2. Assertion : Compounds formed by nonmetals with metals are covalent in nature.
Reason : Compounds formed between nonmetals themselves are largely covalent.
AnswerAnswer:(d) : Compounds formed by non-metals with metals are generally ionic in view of larger differences in their electronegativities. Compounds formed between non-metals themselves are largely covalent in character because of small differences in their electronegativities.
Q.3. Assertion : The tetrahalides of carbon are not hydrolysed by water under normal conditions.
Reason : Carbon cannot expand its coordination number beyond 4 because of the absence of d-orbitals.
Q.4. Assertion : All the trihalides of boron act as Lewis acids.
Reason : The relative strength of boron trihalides is of the order BI3 > BBr3 > BCl3 > BF3
AnswerAnswer:(b) : BF3 is weakest Lewis acid.
Q.5. Assertion : Anhydrous AlCl3 is covalent but hydrated AlCl3 is ionic.
Reason : In water, Al2Cl6 dissociates into hydrated Al3+ and Cl– ions due to high heat of hydration of these ions.
Q.6. Assertion : Al forms [AlF6]3– but B does not form [BF6]3–.
Reason : B does not react with F2.
AnswerAnswer:(c) : B does not have vacant d-orbitals as for B, second shell is the outermost shell.
Q.7. Assertion : Boron differs from aluminium and other members of group 13 in a number of properties.
Reason : Boron shows anomalous behaviour.
AnswerAnswer:(b) : This is due to small atomic size, high electronegativity, high ionization energy and absence of d-orbital of B.
Q.8. Assertion : The tendency for catenation decreases in the order C > Si > Ge > Sn.
Reason : The catenation depends on the strength of the element-element bond.