Designation:D5356−17aStandardTestMethodforpHofChromeTanningSolutions1ThisstandardisissuedunderthefixeddesignationD5356;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1ThistestmethodcoversthedeterminationofthepHofchrometanningsolutions.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D3898TestMethodforChromicOxideinBasicChromiumTanningLiquors3.Terminology3.1DefinitionsofTermsSpecifictoThisStandard:3.1.1pH,ofasolution—thenegativelogarithmofthehydrogenionactivity.3.1.1.1Discussion—AsolutionofpH7isneutralat24°C.Lowernumbersindicateincreasingacidity,highernumbersindicateincreasingalkalinity.4.SummaryofTestMethod4.1Thechrometanningliquorisdilutedtoaconcentrationof25.060.5gchromicoxideequivalentperlitre,allowedtocometoequilibriumandthepHisthenmeasuredwiththeappropriatemeter.5.SignificanceandUse5.1ThistestmethodisdesignedtomeasurethepHofachrometanningsolutionwhichhasbeendilutedtoaspecificconcentration.Thisisconsideredtobeameasureoftheacidityoralkalinityofthesolution.5.2Thistestmethodissuitableforqualitycontrolinthemanufactureofleather.6.Apparatus6.1ElectronicpHMeter,withasuitableelectrode.Themetershallhaveanaccuracyofatleast0.1p...
