Gen. Chem Question

[vanillabear55]

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Which of the following is required to neutralize 5.00 mL of 0.20 M CaCO3 (aq)?

A. 10.0 mL 0.10 N NaOH(aq)
B. 10.0 mL 0.10 N HNO3 (aq)
C. 10.0 mL 0.30 N H3PO4 (aq)
D. 10.0 mL 0.20 N HCl (aq)

Explanation too please, so confused.

Thanks!

 

[Hadi7183]

The answer is D. CaCO3 is dissociated (not really - see below) to Ca2+ and (CO3)2-, which can be considered as a Bronsted-Lowry base and is neutralized by two equivalents of H+. Since you have 5mL*0.2M=1mmol of (Co3)2-, you need 2 mmol of H+, which is the HCl solution in D. The final products are CaCl2 and H20+CO2 (H2CO3).

Keep in mind that CaCO3 is NOT soluble in water, but it can react and get dissolved by a strong acidic solution (e.g., HCl).