The given set-up was arranged by Sachita to find the reactivity order of metals :
She recorded her observations as follows:
1. Clean copper metal did not react with 1 molar solution of metal X nitrate.
2. Clean metal X dissolved in 1 molar solution of metal Y nitrate and metal Y was deposited.
3. Clean metal Y did not react with 1 molar copper nitrate solution.
Metals X and Y could be respectively
