Concept:The sequence involves hydroboration-oxidation, oxidation of a primary alcohol, and a Grignard reaction.Explanation:C3H6 is propene, written as CH3−CH=CH2.Hydroboration-oxidation with BH3 followed by H2O2/NaOH adds water in an anti-Markovnikov manner.Hence the −OH group attaches to the terminal carbon, giving P as 1-propanol.P=CH3−CH2−CH2OHSince P is a primary alcohol, CrO3 in anhydrous medium oxidises it to an aldehyde.Thus, Q is propanal.Q=CH3−CH2−CHOPropanal reacts with CH3MgBr, and the CH3 group adds to the carbonyl carbon.On hydrolysis with H2O, a secondary alcohol is produced.CH3−CH2−CHO+CH3MgBrH2OCH3−CH2−CH(OH)−CH3+Mg(OH)BrTherefore, R is 2-butanol.R=CH3−CH2−CH(OH)−CH3Answer:P = 1-propanol, Q = propanal, R = 2-butanol.