Question

plz answer this with reasons

Answer 1

gas is released in option (2)
because in case- II:zn+hcl givES zncl2 + h2.here h2 is a gas.
in case-4: there is no reaction due to N.a. is more reactive than Al.
in case-1zn+cuso4 givES znso4 +cu
in case-3 fe+cuso4 givES fe2so4+cu

ANSWER IS OPTION 2