Q2 of 29 Page 73

Write down the changes that will be seen in each instance and explain the reason behind it.

Zinc oxide was added to dilute HCl and zinc oxide was added to dilute NaOH.

The changes observe when zinc oxide was added to dilute HCl and zinc oxide was added to dilute NaOH are:

i. With HCl, zinc oxide forms salt and water which shows basic properties.


ii. With NaOH, zinc oxide forms salt and water which shows acidic properties.


Explanation: Zinc oxide is an amphoteric oxide which shows both the properties of an acid as well as a base.


When zinc oxide reacts with HCl (acid), shows basic properties:
ZnO + HCl → ZnCl2 + H2O (basic nature)


When zinc oxide reacts with NaOH (base), shows basic properties:
ZnO +NaOH → Na2ZnO2 + H2O (acidic nature)


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