Question

(a) Write a briefexperimental procedure for the chromic acid test.Include all observations such ascolor change, precipitation, etc.(5 points)(b) What functional groups can be distinguished by this test?(2points)(c) What is the reason for the color change if you get a positive chromic acid test?(3points)(d) Sketch a reaction mechanism for a positive chromic acid test with the above given molecules.(10points) g

Answer 1

Answer:

See explanation

Explanation:

a) -About 1-2 drops of the unknown is dissolved in approximately 1 mL of analytical grade acetone standard solution. The test solution is added and shaken thoroughly.  If a positive test is not immediately observed, the set should be allowed to stand for 1-2 minutes. A positive result means the appearance of a green color.

b) The functional groups that can be distinguished by the test are alcohols and aldehydes.

Aldehydes give a positive test to chromic acid but ketones do not.

Primary and secondary alcohols give a positive test to chromic acid but tertiary alcohols do not.

c) Chromic Acid Test involves Cr in the +6 oxidation state. A positive test implies the reduction of orange Cr^6+ to green chromium Cr^3+.

d) The compounds were not shown but this image attached from lumen learning summarizes the reaction mechanism of chromic acid test.