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Stella asked in 科學及數學化學 · 7 years ago

A chemical question

In an accident, some HCl was split out. Which of the following substances, when added in excess, would neutralize the acid without leaving any alkaline solution?

A) NaOH

B) Limewater

C) CaCO3

D) H2O

Why is the answer C?

1 Answer

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    Lv 7
    7 years ago
    Favorite Answer

    The answer is : (C) CaCO3

    (A) incorrect

    NaOH can be used to neutralize HCl.

    NaOH + HCl → NaCl + H2O

    When NaOH is added in excess, a part of NaOH neutralizes the HCl. The unreacted NaOH will be left as an alkaline solution.

    (B) incorrect

    Lime water is Ca(OH)2 solution, which can be used to neutralize HCl.

    Ca(OH)2 + 2HCl → CaCl2 + 2H2O

    When limewater is added in excess, a part of Ca(OH)2 neutralizes the HCl. The unreacted Ca(OH)2 will be left as an alkaline solution.

    (C) correct

    CaCO3 can be used to neutralize HCl.

    CaCO3 + 2HCl → CaCl2 + H2O + CO2

    When CaCO3 is added in excess, a part of CaCO3 neutralizes the HCl. The unreacted CaCO3 solid is insoluble in water and thus no alkaline solution is left.

    (D) incorrect

    H2O can be used to dilute the HCl, but it cannot neutralize the HCl.

    Source(s): 土扁
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