Question #7013e

1 Answer
Apr 22, 2017

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