cdigital.dgb.uanl.mxcdigital.dgb.uanl.mx/la/1030011061/1030011061_053.pdf · liquid is tested by...
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cdigital.dgb.uanl.mxcdigital.dgb.uanl.mx/la/1030011061/1030011061_053.pdf · liquid is tested by red and blue litmus-paper to ascertain if free alkalies, free acids, or neither are