Question

question 4 (1 point)
which combination of aqueous solutions should produce a precipitate?
a) nach3coo and hcl
b) koh and ca(no3)2
c) kno3 and cacl2
d) agno3 and ca(ch3coo)2
e) naoh and hcl

Explanation:

Step1: Check for precipitation in option a

Sodium acetate (\(NaCH_3COO\)) and hydrochloric acid (\(HCl\)) react to form acetic acid (\(CH_3COOH\)) and sodium chloride (\(NaCl\)). Both acetic acid and sodium chloride are soluble in water. So, no precipitation occurs.

Step2: Check for precipitation in option b

Potassium hydroxide (\(KOH\)) and calcium nitrate (\(Ca(NO_3)_2\)) react. The products are potassium nitrate (\(KNO_3\)) and calcium hydroxide (\(Ca(OH)_2\)). Calcium hydroxide has low solubility but is not a typical "precipitate" in the context of such questions (it's more of a slightly - soluble compound, and in many cases, especially in basic aqueous solution comparisons, it's not considered a precipitate for this type of multiple - choice).

Step3: Check for precipitation in option c

Potassium nitrate (\(KNO_3\)) and calcium chloride (\(CaCl_2\)): According to the solubility rules, all nitrates are soluble, and most chlorides are soluble (calcium chloride is soluble). So, no precipitation occurs.

Step4: Check for precipitation in option d

Silver nitrate (\(AgNO_3\)) and calcium acetate (\(Ca(CH_3COO)_2\)): Silver acetate (\(AgCH_3COO\)) is insoluble in water. The reaction is \(2AgNO_3+Ca(CH_3COO)_2 = 2AgCH_3COO\downarrow+Ca(NO_3)_2\)

Step5: Check for precipitation in option e

Sodium hydroxide (\(NaOH\)) and hydrochloric acid (\(HCl\)): They react to form sodium chloride (\(NaCl\)) and water. Sodium chloride is soluble in water. So, no precipitation occurs.

Answer:

d) \(AgNO_3\) and \(Ca(CH_3COO)_2\)