Reactions involved areC2​H6​+Br2​2C2​H5​Br+2Na​⟶C2​H5​Br+HBr→C4​H10​+2NaBr​Actual yield of C4​H10​=55 g which is 85% of theoretical yield.⇒ Theoretical yield of C4​H10​=8555×100​=64.70 gAlso, 2 moles ( 218 g) C2​H5​Br gives 58 g of butane.⇒64.70 g of butane would be obtained from582​×64.70=2.23 moles C2​H5​BrAlso yield of bromination reaction is only 90%, in order to have 2.23 moles of C2​H5​Br, theoretically902.23×100​=2.48 moles of C2​H5​Br required. Therefore, moles of C2​H6​ required =2.48⇒ Volume of C2​H6​(NTP) required =2.48×22.4=55.55 L.