Question

Question 11.26 (a) Classify following oxides as neutral, acidic, basic or amphoteric:

CO, B2O3, SiO2, CO2, Al2O3, PbO2, Tl2O3

(b) Write suitable chemical equations to show their nature.

Class XI The p-Block Elements Page 325

Answer 1

(a) neutral oxides : CO
acidic oxides : B2O3 , SiO2 , CO2
basic oxides : Tl2O3 ,
Amphoteric oxides : Al2O3 , PbO2


(b) (i) being acidic B2O3 , SiO2 and CO2 react with alkali to form salts .
B2O3 + 2NaOH -----> 2NaBO2 + H2O;
SiO2 + 2NaOH ------> Na2SiO3 + H2O;
CO2 + 2NaOH -------> Na2CO3 + H2O

(ii) being Amphoteric , Al2O3 and PbO2 react with both acids and bases .
Al2O3 + 3H2SO4 ------>Al2(SO4)3 + 3H2O
Al2O3 + 2NaOH -------> NaAlO2 + H2O

2PbO2 + 2H2SO4 ----->PbSO4 + 2H2O +O2
PbO2 + 2NaOH -------> Na2PbO3 + H2O

(iii) Being basic Tl2O3 reacts with acid .
Tl2O3 + 6HCl ------> 2TlCl3 + 3H2O

Answer 2

Answer:

Neutral oxides: CO

Acidic oxides: B 2 O 3 ,SiO 2 and CO 2 Amphoteric oxides: Al 2 O 3 and PbO 2

Basic oxide: Tl 2 O 3 .