The reaction h2so4 + 2 naoh -> na2so4 + 2h2o applied to an acid-base tritration. the equivalence point occurs when 26.66 ml of 0.1923 m naoh is added to a 42.45 ml portion of h2so4. calculate the original [h2so4].

We make use of ratios to solve this question.
            moles NaOH = c · V = 0.1923 mmol/mL · 26.66 mL = 5.126718 mmol
            moles H2SO4 = 5.126718 mmol NaOH · 1 mmol H2SO4 / 2 mmol NaOH = 2.563359 mmol
Hence
            [H2SO4]= n/V = 2.563359 mmol / 42.45 mL = 0.06039 M
The answer to this question is  [H2SO4] = 0.06039 M

B. a graduated substance

Your awser would be a acetone