If `0.228 g` of silver salt of dibasic acid gabe a residue of `0.162 g` of silver on ignition then molecular weight of the acid is

Options

A. 70
B. 80
C. 90
D. 100

Answer

C

Explanation

Mass of silver salt taken = 0.228 g
Mass of silver left = 0.162 g
Basicity of acid = 2
Step 1 : To calculate the equivalent mass of the silver salt (E)
`("Eq. Mass of silver salt")/("Eq. Mass of silver") = ("Mass of Acid taken")/("Mass of silver left")`
`E/108 = 0.228/0.162`
`= E = 0.228/0.162 xx 108 = 152`
Step 2 : To calculate the equivalent mass of acid.
Eq. mass of acid = Eq. mass of silver salt – Eq. mass of Ag + Basicity
`= 152 - 108 + 1 153 - 108 = 45` (Eq. mass of acid)
Step 3 : To determine the molecular mass of acid.
Mol. mass of the acid = Eq. mass of acid `xx` Basicity
`= 45 xx 2 = 90`