Account for the following observations:

(i) AlCl₃ is a Lewis acid                                    (ii) Though fluorine is more electronegative than chlorine yet BF₃ is a weaker Lewis acid than BCl₃      

_{(iii) PbO2 is a stronger oxidising agent than SnO2       (iv) The +1 oxidation state of thallium is more stable than its +3 state.}

This is a Assertion and Reason Type Questions as classified in NCERT Exemplar

(B)

Silicones are a class of silicon polymers that contain the repeating unit (-R 2 SiO-). Silicones are water repellent in nature because they are surrounded by non-polar alkyl groups, so A and R are both correct, but R is not the correct explanation of A.

This is a Assertion and Reason Type Questions as classified in NCERT Exemplar

(A)

In aluminium silicate, silicon is doped with group 13 elements and as aluminium is trivalent and silicon is tetravalent so, on replacing aluminium by Silicon, a negatively charged structure will be obtained. Both the statements assertion and reason are correct and reason is the correct explanation of assertion.

This is a Matching Type Questions as classified in NCERT Exemplar

(i)→ (b), (ii) → (c), (iii) → (b), (iv) → (a) (v)→ (b) (vi)→ (c)

This is a Matching Type Questions as classified in NCERT Exemplar

(i)→ (c) (ii)→ (d) (iii)→ (a) (iv)→ (e) (v)→ (b)

This is a Matching Type Questions as classified in NCERT Exemplar

(i)- (e), (ii)- (c), (iii)- (d), (iv)- (a) & (b)