Which salt is best prepared by Titration ? A      barium sulfate B      calcium carbonate C      lead(II) nitrate D      potassium chloride

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A salt can be produced by titration under two conditions:

1. If it’s soluble so that it precipitates out of solution.

2. If there’s a change in pH, color or conductivity that allows for detection of a titration endpoint.

Out of the choices, barium sulfate best meets these conditions. It has very low solubility in water and precipitates according to the following net ionic equation:

`Ba^(2+)_(aq) + SO_4^(2-)_(aq)-> BaSO_4(s)`

The reaction of barium hydroxide with sulfuric acid is a neutralization reaction in which the endpoint can be detected by monitoring the change in pH and/or by using an indicator:

`Ba(OH)_2 + H_2SO_4-> 2 H_2O + BaSO_4`

At the endpoint the solid barium sulfate can be filtered and dried.

The other salts mentioned don’t lend themselves to this technique for the following reasons:

Lead(II)nitrate and potassium chloride are both soluble in water and therefore don’t precipitate as solids.

Precipitation reactions that produce calcium carbonate don’t have observable titration endpoints. CaCO3 can be precipitated through the reaction of soluble salts such as sodium carbonate and calcium chloride, but there’s no color change and little or no change in pH. A neutralization reaction using carbonic acid wouldn’t yield favorable results due to the tendency of carbon dioxide to outgas from the solution.

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