The products A and B obtained in the following reactions, respectively, are: $3\text{ROH} + \text{PCl}_3 \rightarrow 3\text{RCl} + \text{A}$ $\text{ROH} + \text{PCl}_5 \rightarrow \text{RCl} + \text{HCl} + \text{B}$

According to the methods of preparation of haloalkanes from alcohols:

1. The reaction of an alcohol with phosphorus trichloride ($\text{PCl}_3$) yields an alkyl chloride along with phosphorous acid ($\text{H}_3\text{PO}_3$). Therefore, product A is $\text{H}_3\text{PO}_3$ . $3\text{R-OH} + \text{PCl}_3 \rightarrow 3\text{R-Cl} + \text{H}_3\text{PO}_3$

2. The reaction of an alcohol with phosphorus pentachloride ($\text{PCl}_5$) yields an alkyl chloride, phosphoryl chloride ($\text{POCl}_3$), and hydrogen chloride gas. Therefore, product B is $\text{POCl}_3$ . $\text{R-OH} + \text{PCl}_5 \rightarrow \text{R-Cl} + \text{POCl}_3 + \text{HCl}$

Thus, A and B are $\text{H}_3\text{PO}_3$ and $\text{POCl}_3$, respectively.