83.235 grams of CaCl2 is required to make 1 litre of 0.75M solution.
Explanation:
Molarity or molar concentration is the number of moles of solute that can be dissolved in 1 L of a solution.
let us find the number of moles 
n=C*V                Concentration is 0.75M
                           Volume is 1000ml.
n= 0.75*1
 n= 0.75 
This means there are 0.75 moles of CaCl2 in 1000 ml of solution of .75M.
Molar mass of CaCl2 is = 40.08+ 2(35.5)
                                        =   110.98 gms
Thus 1 MOLE OF CaCl2 weighs 110.98
          so 0.75 moles will weigh  110.98*0.75
                                               =  83.235 grams of CaCl2 is required to make 1 litre of 0.75M solution.