Question

Assertion- Metals like Lead, Aluminium, Iron and Zinc do not react either withcold or hot water at all.Reason-By the formation of lead oxide and other oxide on the surface they do notreact with water. ​

Answer 1

Answer:

both assertion and reason are true and reason os correct explanation of assertion

Answer 2

Let us answer it

Explanation:

Metals

They always loose electron and form electropositive ions .

Reaction of metals with water

Whenever metals react with water they form metal hydroxides and along with it hydrogen gas is evolved .

That is : M + H₂O--> M(OH)ₓ + H₂

                                   Metal hydroxides

The reaction of metals with water depend upon their re-activities and that can be known by considering reactivity series that is :

K>Na>Ca>Mg>Al>Zn>Fe>Sn>Pb>H>Cu>Hg>Ag>Au>Pt

1.Now it is seen that metals such as K,Na  react with cold water as their hydroxides are quite stable :

Na +H₂O-->NaOH +H₂

   (cold water)

2.The metals such as Mg , Ca react with hot water , as their reaction with water need a certain initiation (that is heat )

Mg +H₂O-->Mg(OH)₂ + H₂

( hot water  )

3.But Metals like Lead, Aluminium, Iron and Zinc do not react either with cold or hot water at all - because of the formation of oxide layer on its surface which prevent further reaction .

Al + H₂O --> Al₂O₃ + H₂

In this case instead of hydroxide , oxide layer is formed that performs the perfect coating and prevent further reaction .

4.    Metals below H that is Cu,Hg,Ag,Au Pt do not react with water as they are less reactive that H , so can't reduce it .Therefore no reaction .

So, in the above asked question we can answer it as :

Yes, this is true that Metals like Lead, Aluminium, Iron and Zinc do not react either with cold or hot water at all - because of the formation of oxide layer on its surface which prevent further reaction .