Question

Question #7013e

Answer 1

Refer to the explanation

Explanation:

First, find the moles of `NaOH` using the formula of `n = c*v`
number of moles = `(volume)/1000 *concentration`

moles = `(40)/1000*0.2`

moles = 0.008

Then here is the balanced equation of the neutralisation reaction while having the unknown dibasic acid.

`H_2X + 2NaOH -> 2H_2O + Na_2X`

Mole ratio is 1:2 so you divide the moles of the NaOH by 2.

`0.008/2` =0.004

Then we use the formula moles = `(mass)/(A_r or M_r)`

`M_r = (mass)/ (m)`

`0.2/(0.004)` = 50

Relative molecular mass of acid A is 50