Question

which metal does not react with dilute sulphuric acid to liberate H2 gas.

Answer 1

The ones which can liberate hydrogen are more reactive than hydrogen.
Hydrogen has 0 reduction potential. The ones with -ve reduction potential can liberate hydrogen.

Cu has +ve reduction potential, hence can't liberate hydrogen.
Zn has -ve reduction potential, hence can liberate hydrogen

So, Cu doesn't react to liberate hydrogen