Answer
All three test tubes contain a saturated solution of BaSO4. The addition of either barium or sulfate ions will shift the reaction to the left, causing BaSO4 to precipitate out of the saturated solution. This is called the common ion effect. The addition of NaCI, which, having no common ions with
BaSO4, would have no effect on the solution. Choices a and c show a precipitate forming. Only b remains unchanged. So, b is the correct answer.
Work Step by Step
All three test tubes contain a saturated solution of BaSO4. The addition of either barium or sulfate ions will shift the reaction to the left, causing BaSO4 to precipitate out of the saturated solution. This is called the common ion effect. The addition of NaCI, which, having no common ions with
BaSO4, would have no effect on the solution. Choices a and c show a precipitate forming. Only b remains unchanged. So, b is the correct answer.
