Question

Of the three metals X, Y and Z. X reacts with cold water, Y with hot water and Z with steam only. Identify X, Y and Z and also arrange them in order of increasing reactivity.

Answer 1

Hi !

X reacts with cold water. 
Hence , the element can be "Calcium"

Ca + H₂O ---> Ca(OH)₂ + H₂

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Y reacts with hot water,
Hence, it is "Magnesium"

Mg + H₂O ---> Mg(OH)₂ + H₂

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Z reacts with steam only.
Hence , it can be "Iron"

Fe + H₂O ---> Fe₂O₃+  H₂
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Arranging in ascending order (increasing order of reactivity)

Fe < Mg < Ca

Answer 2

X is alkali metal ,Na or K

Y is an alkaline earth metal Mg or ca

Z is fe

Increasing order na/ mg/ fe