... WWW.VIETMATHS.COM Gii: cỏch 1: thi gian t giõy thỡ necho=ne nhn=0,035.4e=0,14 mol e thi gian 2t giõy thỡ necho=ne nhn=0.28 mol e., nờn khớ anot nO2=0,28:4=0,07 ... in cc tr, cng dũng in khụng i) thi gian t giõy, p dng ppbt e ta cú: 4.nO2 2.nM nM 0, 07 mol nM 0, 07 mol in phõn X (vi in cc tr, cng dũng in khụng i) thi gian 2t giõy, nO2 2.0, 035 ... tm thi ca nc l: A HCl, NaOH, Na2CO3 B NaOH, Na3PO4, Na2CO3 C KCl, Ca(OH)2, Na2CO3 D HCl, Ca(OH)2, Na2CO3 Gii: -Nguyờn tc lm mm nc cng l gim nng cỏc cation Ca2+, Mg2+, nc cng, i vi nc cng tm thi...