Assertion : AlF₃ is soluble in KF but addition of BF₃ brings its precipitation. Reason BF₃ is more acidic than AlF₃.

3 AlF is soluble in KF. 3 3 6 AlF 3KF K AlF + ® 3 6 3 3 4 insoluble K AlF BF AlF 3K BF + ® + Because 3 BF , is more acidic then 3 AlF .