During the purification of benzocaine methanol is used to

During the purification of benzocaine methanol is used to purify in the later steps of purification where as ethanol is used during the synthesis process. Why is methanol used instad of the ethanol the second round? Also 10% aqueous sodium carbonate is used to nuetralize the sulfuric acid used i know how to calculate how much sodium carbonate should be used but not 10 percent aqueous sodium carbonate.