When aqueous solution of borax is acidified with hydrochloric acid, a white crystalline solid is formed which is soapy to touch. Is this solid acidic or basic in nature? Explain.

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)