The one that does not stabilize 2$$^\circ$$ and 3$$^\circ$$ structures of proteins is

Lime reacts exothermally with water to give 'A' which has low solubility in water. Aqueous solution of 'A' is often used for the test of CO$$_2$$, a test in which insoluble B is formed. If B is further reacted with CO$$_2$$ then soluble compound is formed, 'A' is :

Which of the following is used as a stabilizer during the concentration of sulphide ores?

The major product 'P' formed in the given reaction is