Rate of reaction

[匿名]

2012-11-24 4:51 am

Which of the following is a factor affecting the reaction rate of the following reaction?

Mg (s) + 2 HCl(aq) ------> MgCl2 (aq) + H2 (g)

A) Concentration of HCl (aq)
B) Concentration of Mg (s)
C) Concentration of MgCl2 (aq)
D) Concentration of H2 (g)

I know the answer is A... But can anyone explain me why B is not correct?

回答 (1)

不用客氣

2012-11-24 7:33 am

✔ 最佳答案

The answer is : A) Concentration of HCl(aq)

A) correct
The rate of reaction is affected by the concentration of aqueous or gaseousreactants.

B) incorrect
Mg is a solid. The concentration(mass/volume or mole/volume) of a solid does NOT affect the rate of reaction,because it is CONSTANT.
For a solid reactant like Mg(s), only its surface area affects the rate ofreaction. The larger the surface area ofa solid reactant, the faster the reaction rate is.
If more magnesium is used but the surface area of magnesium does not increase,the reaction rate is unchanged.

C) and D) incorrect
The concentration of a product does NOT affect the rate of reaction.

參考: 不用客氣

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