Question

please solve this equation and give reason

Answer 1

HELLO FRIEND!

[I saw in the comments section that you asked for the last two of Question number 19, so I am answering only them. In case you have any problem with the other reactions, please feel free to message me, I shall edit my answer].

Now, to answer your question,

Zn + 2NaOH ------> Na₂ZnO₂ + H₂
Zinc is an amphoteric metal, so it reacts with acids as bases to form Hydrogen gas. Na₂ZnO₂ is Sodium zincate.


Al + KOH + 2H₂O ------> KAlO₂ + 2H₂
Aluminium is also an amphoteric metal.




Resoning:

(i) Lead is a less reactive metal. Again, Lead chloride and Lead sulphate are insoluble salts. When lead reacts with sulphuric acid, a layer of insoluble lead sulphate is formed, which stops further reaction. When lead reacts with hydrochloric acid, a layer of lead chloride is formed, which stops further reaction. Thus, hydrogen gas is not evolved.


(ii) Potassium and sodium are two most reactive metals (alkali metals). They react strongly with water and other acids. It can also lead to a fire. Hence, to avoid any accident, they are not used in the laboratory.



THANKS (^_^)