The molar mass of KCl is 74.6 g multiply that by 2.45 and you get 182.8 g which is the amount you would need to make 1000 mL of solution. Divide that by 20 to get the amount for 50 mL because 50 is 1/20 of 1000. 9.14 g is needed.
How Many Grams Of KCl Are Needed To Make 50.0 ML Of 2.45 M KCl?