Calculate the molar concentration of H2S equivalent if 10.17 ml of sodium hydroxide titrant (c1/zT) = 0.095 mol/L is used to titrate an aliquot part of a 10.0 ml solution of this substance. Write: a) reaction scheme; b) factors of equivalence of participants of reaction; c) the expression of the law of equivalents for this reaction; d) type of chemical reaction (titration method); e) indicator for determination of equivalence point (choice to explac)