The equivalent mass of a certain bivalent metal is 20 . The molecular mass of its anhydrous chloride is

Options

A. 91
B. 111
C. 55.5
D. 75.5

Answer

B

Explanation

Let the compound be `MCl_(2)`
Equivalent mass of a metal ion = `("Atomic mass")/("Total positive valency")`
`20 = ("Atomic mass of the metal ion")/(2)`
`implies` Atomic mass of the metal = `2 xx 20 = 40`
`therefore` Molecular mass of anhydrous chloride `(MCl_(2))`
`= 40 + (2 xx 35.5)`
`= 40 + 71 = 111`