0.59g of the silver salt of an organic acid (mol.wt.210) on ignition gave 0.36g of pure silver. The basicity of the acid is [At.Wt of $Ag=108$ ]

$\frac{Eq.wtofsilversalt}{Eq.wtofpuresilver}=\frac{MassofSilverSalt}{Massofpuresilver}$

$\frac{E}{108}=\frac{0.59}{0.36}$

$E=\frac{0.59\times 108}{0.36}=177$

Eq. Mass of organic acid = eq. mass of silver salt --- eq. mass of silver  + 1
 $\begin{array}{l}=177-108+1\\ =70\end{array}$
Basicity  $=\frac{Massoforg.acid}{Eq.Mass}=\frac{210}{70}=3$