Which of the following complex species is not expected to exhibit optical isomerism?

An unknown alcohol is treated with the “Lucas reagent” to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism:

A compound with molecular mass 180 is acylated with CH₃COCl to get a compound with molecular mass 390. The number of amino groups present per molecule of the former compound is:

The gas leaked from a storage tank of the Union Carbide plant in Bhopal gas tragedy was: