# The formula weight of an acid is 82.0.$100cm^3$ of a solution of this acid containing 39.0g of the acid per litre were completely neutralized by $95.0cm^3$ of aqueous NaOH containing 40.0g of NaOH per litre.What is the basicity of the acid?

$(a)\;1\qquad(b)\;4\qquad(c)\;3\qquad(d)\;2$

$n$ is basicity of acid
Normality of acid =$\large\frac{39}{82/n\times 1}$
Normality of NaOH =$\large\frac{40}{40}\times \frac{1000}{1000}$$=1 \therefore \large\frac{39n}{82}$$\times 100=1\times 95$
$n=2$
Hence (d) is the correct answer.