Answer:
2 M
Explanation:
mole weight of CaBr2 = 40 + 2 * 79.9 = 199.8 gm
20 gm is then 20/199.8 =.1 mole
.1 mole / .50 liter = 2 M
C. Lithium
I Goo gled it and I think that's right.