Answer:
~2.054M
Step-by-step explanation:
In this question ,I am going to assume that the acid is monoprotic acid(contains only one hydrogen) which I'll represent by HA.
Chemical equation:
NaOH(aq) + HA(aq)----->NaA(aq) + H2O(l)
The mole ratio of NaOH:HA is 1:1
1.25M NaOH=1.25 Moles/L or 1.25 moles /1000ml of NaOH
(1.25 moles /1000ml) x (24.65ml)=0.0308125 moles NaOH
Mole ratio is 1:1
So, moles of HA are also 0.0308125 moles
volume of HA =15ml
To find molarity of HA:
=(0.0308125 moles x 1000ml)/(15ml)
~2.054M of HA
~Hope it helps:)