Answer:
56
Step-by-step explanation:
Given that the metal chloride formula is MC13, we can assume that the metal (M) is represented by the atomic symbol "M" and the atomic weight of chlorine (Cl) is 35.5.
Since 20% of the total weight of the compound is the metal, the atomic weight of the metal (M) can be calculated as:
M = (0.2 * (13 * 35.5 + M)) / 13 = 0.2 * 35.5 + 0.2 * M
Solving for M:
0.2 * M = (0.2 * 35.5) / (1 - 0.2) = 7.1
M = 7.1 / 0.2 = 35.5
So the atomic weight of the metal (M) is 35.5, and the answer is (b) 56.