S Block Elements Question 84
Question: The main oxides formed on combustion of $ Li,Na $ and K in excess of air are, respectively:
Options:
A) $ Li_2O_2,Na_2O_2 $ and $ KO_2 $
B) $ Li_2O,Na_2O_2 $ and $ KO_2 $
C) $ Li_2O,Na_2O $ and $ KO_2 $
D) $ LiO_2,Na_2O_2 $ and $ K_2O $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] On heating with excess of air $ Li,Na $ and $ K $ forms following oxides $ 4Li+O_2\xrightarrow{{}}\underset{Lithiummonoxide}{\mathop{2Li_2O}} $
$ 4Na+O_2\xrightarrow{575K}\underset{Sodiumperoxide}{\mathop{Na_2O_2}} $
$ K+O_2\xrightarrow{{}}\underset{~Potassiumsuperoxide}{\mathop{KO_2}} $
BETA
