[单选题]
Magnesium and excess hydrochloric acid react together to produce hydrogen gas. This experiment was conducted two times with different hydrochloric acid concentrations but with the same magnesium mass.
In both cases, the volume of hydrogen gas produced was measured at different times, and graphs 1 and 2 were plotted accordingly, as shown below. Choose the letter representing the stage where the rate of reaction is the fastest.
A.
B.
C.
D.
参考答案: D
本题详细解析: D
D has the steepest gradient when a tangent is drawn.
