1. In titration analysis, the sudden change of indicator color is generally used to determine the arrival of stoichiometric point, and the titration is stopped when the indicator changes color.This point is called ( ).
A. titration analysis
B. titration
C. stoichiometric point
D. endpoint of titration
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Which of the following statements is not true?( )
A. The content of any substance capable of redox reaction can be determined by a direct method
B. Acid-base titration is a kind of titration analysis method based on proton transfer reaction
C. Rapid reaction rate is one of the important conditions for titration analysis
D. Chemical reactions suitable for direct titration must be quantitative
The correct description about the molecular ion peak is ( ).
A. The mass-to-charge ratio of the molecular ion peak is equal to the relative molecular mass of the compound
B. The peak with the largest mass is the molecular ion peak
C. The second highest mass peak is the molecular ion peak
D. The most intense peak is the molecular ion peak
Among the following compounds, which has the weakest molecular ion peak? ( ) .
A. aromatic ring
B. conjugated alkenes
C. ester
D. alicyclic compound
In the mass spectrum of the compound C2H5Br, the relative intensity ratio of the M and M+2 peaks is about ( ) .
A. 1:1
B. 2:1
C. 3:1
D. 4:1
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