Name: Electronic Arrangement of s-block Elements
Uploaded: 2019-07-19
Duration: 24 min 8 s
Description: Do you know how to write the electronic configuration of s-block elements? Is there any similarity in the electronic configuration of all the members of the...

Question

Which of the following methods would you use to extinguish a fire of lithium, sodium or potassium metals? Explain why some of these are unsuitable and give the reactions involved.
(a) Water
(b) Dinitrogen
(c) Carbon dioxide
(d) Asbestos blanket

Accepted Answer

(a) Water does not help in extinguishing a fire because when it reacts with alkali metals, it liberates hydrogen which is an inflammatory gas.

$Li + H_{2} O \to LiOH + H_{2} ↑$

$Na + H_{2} O \to NaOH + H_{2} ↑$

$K + H_{2} O \to KOH + H_{2} ↑$

(b) Dinitrogen reacts with lithium to form lithium nitride while other reactants are inert towards $N_{2}$ . Lithium nitride on contact with water gives ammonia. So, it cannot be used for extinguishing a fire.

$4 Li + 3 N_{2} \to 2 {Li}_{2} N_{3}$

(c) Carbon dioxide is used to extinguish a fire of lithium, sodium and potassium. This is because ${CO}_{2}$ does not help in burning and also reacts with alkali metals to form carbonates. The thermal stability of the carbonates increases down the group.

$4 Li + 3 {CO}_{2} \to 2 {Li}_{2} {CO}_{3}$

$4 Na + 3 {CO}_{2} \to 2 {Na}_{2} {CO}_{3}$

$4 K + 3 {CO}_{2} \to 2 K_{2} {CO}_{3}$

(d) Asbestos blanket is a silicate and stops the flow of oxygen. It was used as an insulator in previous days because of its resistance towards fire, corrosion and chemical nature. But due to its toxic and carcinogenic nature, it is not preferred.

Which of the following methods would you use to extinguish a fire of lithium, sodium or potassium metals? Explain why some of these are unsuitable and give the reactions involved.
(a) Water
(b) Dinitrogen
(c) Carbon dioxide
(d) Asbestos blanket

Important Questions on Group 1 - the Alkali Metals

Learn and Prepare for any exam you want !

Which of the following methods would you use to extinguish a fire of lithium, sodium or potassium metals? Explain why some of these are unsuitable and give the reactions involved. (a) Water (b) Dinitrogen (c) Carbon dioxide (d) Asbestos blanket

Important Questions on Group 1 - the Alkali Metals

Learn and Prepare for any exam you want !

Which of the following methods would you use to extinguish a fire of lithium, sodium or potassium metals? Explain why some of these are unsuitable and give the reactions involved.
(a) Water
(b) Dinitrogen
(c) Carbon dioxide
(d) Asbestos blanket