2,3-dichlorobutane has two chiral centers, which are carbons 2 and 3. To determine the number of stereoisomers, we can use the formula 2^n, where n is the number of chiral centers. In this case, n = 2, so there are 2^2 = 4 possible stereoisomers.Here are the structures of the four stereoisomers, with the configuration of each stereocenter indicated:1. 2R,3R -2,3-dichlorobutane H H Cl | | |H3C-C-C-C-CH3 | | | Cl H H2. 2R,3S -2,3-dichlorobutane meso compound H H Cl | | |H3C-C-C-C-CH3 | | | H Cl H3. 2S,3S -2,3-dichlorobutane H Cl H | | |H3C-C-C-C-CH3 | | | Cl H H4. 2S,3R -2,3-dichlorobutane meso compound H Cl H | | |H3C-C-C-C-CH3 | | | H H ClNote that two of these stereoisomers, 2R,3S -2,3-dichlorobutane and 2S,3R -2,3-dichlorobutane, are meso compounds, which means they have an internal plane of symmetry and are optically inactive. The other two stereoisomers, 2R,3R -2,3-dichlorobutane and 2S,3S -2,3-dichlorobutane, are enantiomers and are optically active.