Question

what is the molarity of the solution obtained by mixing 75 ml of 0.5M HCl and 75 ml of 0.25M sulphuric acid

Answer 1

From the theorem of equivalence,
Molarity of the solution obtained by mixing 75 mL each of 0.5M and 0.25M H2SO4 = ( (0.5M*75 mL) + (0.25M*75 mL) )/ (75*2) mL
= 75 mL * (0.5M + 0.25M) / (75*2) mL
= 0.75M / 2
= 0.375M