Based on the activity series, which one of the reactions below will occur? mn (s) + nicl2 (aq) → mncl2 (aq) + ni (s) fe (s) + zncl2 (aq) → fecl2 (aq) + zn (s) pb (s) + nii2 (aq) → pbi2 (aq) + ni (s) snbr2 (aq) + cu (s) → cubr2 (aq)

The reaction that will occur are:

Explanation:

In the activity series, a higher metal can displace a lower metal from its salt.

Mn is placed in a higher position than Ni in the activity series. Hence, it is able to displace Ni from its salt  .

All the other reactions are not feasible based on the activity series.

The link for the activity series I referred is given below:

https://studylib.net/doc/9281468/topic-9.1-activity-series

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.