Question

0.84g.of an acid of molecular weight 225 is present in 100ml of the solution 25ml of this solution required 28ml of N/10 NaOH solution for complete neutralisation the basic ity of the acid is

Answer 1

Given that,

Mass of acid = 0.84 g

Weight = 225

We need to calculate the  number of moles of acid

Using formula of number of moles

$N=\dfrac{m}{M}$

Put the value into the formula

$N=\dfrac{0.84}{225}$

$N=3.7\times10^{-3}\ moles$

We need to calculate the number of moles of NaOH needed to neutralize

Using formula of  the number of moles

$\text{number of moles of NaOH needed to neutralize}=0.1\times28\times10^{-3}$

$\text{number of moles of NaOH needed to neutralize}=2.8\times10^{-3}\ moles$

We need to calculate the basicity

Using formula of basicity

$n=\dfrac{\text{number of moles of acid}}{\text{number of moles of NaOH}}$

Put the value into the formula

$n=\dfrac{3.7\times10^{-3}}{2.8\times10^{-3}}$

$n=1.32$

We need to calculate the equivalent weight of the acid

Using formula of equivalent weight

$W'=\dfrac{W}{n}$

Put the value into the formula

$W'=\dfrac{225}{1.32}$

$W'=170.4$

Hence, The equivalent weight of the acid is 170.4