Which of the following substances can reduce the electrode potential of Fe2+/ Fe?
A. NaOH
B. HCl
C. FeCl3
D. None of them
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Which of the following substances cannot be used as a reference substance?
A. Na2B4O7·10H2O
B. Na2CO3
C. KOH
D. H2C2O4·2H2O
If the NaOH solution is not used for a long time, the concentration will change, so it should be re-calibrated before use.
Only results with high accuracy and high precision at the same time are reliable.
1H NMR spectrum of a compound (C5H10O) shows only two single peaks. The structural formula of the compound should be ( ).
A. CH3CH2CH2COCH3
B. (CH3)2CHCOCH3
C. (CH3)3CCHO
D. CH3CH2COCH2CH3