What volume of 18N H2SO4 is required to prepare 125 ml of 6.0 N
mLa x Na = mLb x Nb
mLa x 18 = 125 mL x 6.0
Solve for mL of the 18N solution, take that volume, place in a 125 mL volumetric flask, add distilled water to the mark on the flask, stopper, mix thoroughly, label. done.