Answer:
3.1 mol
Step-by-step explanation:
The balanced equation is
CaCl₂ + 2AgNO₃ ⟶ Ca(NO₃)₂ + 2AgCl
You want to convert moles of AgNO₃ to moles of CaCl₂.
The molar ratio is 2 mol AgNO₃:1 mol CaCl₂
Moles of CaCl₂ = 6.2 mol AgNO₃ × (1 mol CaCl₂/2 mol AgNO₃)
Moles of CaCl₂ = 3.1 mol CaCl₂
The reaction will require 3.1 mol of CaCl₂.