Question

Excess dilute hydrochloric acid was added to an alloy of copper and zinc in a beaker.

1. State the observations made.
2. Excess aqueous sodium hydroxide was added to 2cm3 of the solution obtained in the reaction. Write an ionic equation for the reaction that occurred. 

Answer 1

1. Fizzing/Effervescence/production of gas bubbles
   Colorless solution formed 
   Brown residue/solid 
2. Zn²⁺(aq) + 4OH⁻(aq) → (Zn(OH)₄)²⁻(aq)
   OR
   Zn(OH)₂)(s) + 2OH⁻(aq) → (Zn(OH)₄)²⁻(aq)