Assume that you have an unknown consisting of an aqueous solution of a salt that contains one of the ions listed above. Which ions must be absent on the basis of each of the following observations of the unknown?

a. CO3

b. Cr2O7

c. NH4

d. Ba

e. Al

Check the answers in the explanation

Explanation:

The following are the answers

(1) if the solution is colourless : The answer is B Cr207

(2) If the solution gives no apparent reaction with dilute hydrochloric acid, : The answer is A CO3

(3) if No odour can be detected when a sample of the solution is added drop by drop to a warm solution of sodium hydroxide : The answer is C NH4

(4) If No precipitate is formed when a dilute solution of H2SO4 is added to a sample of the solution : The answer is D ba