Answer:
0.01504 mol/dm3
Explanation:
Calcium Hydroxide - Ca(OH)2
Hydrochloric acid - HCl
The reaction between both is given as;
2HCl + Ca(OH)2 --> CaCl2 + 2H2O
2 : 1
The relationship between the concentration and volume is given as;
CaVa / CbVb = na / nb
where a = acid (HCl) and b = base Ca(OH)2
Inserting the values;
0.04 * 18.8 / (Cb * 25) = 2 / 1
0.752 / 25Cb = 2
Cb = 0.752 / 50 = 0.01504