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`=1.62 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 salt")`
`=(E)/(108)=(0.228)/(0.162)`
`E=(0.228)/(0.162)xx108=152`
`(` Eq. mass of silver salt `)`
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
`=45xx2=90`