When looking for synonyms for the phrase "normal solution", there are a number of options available. One alternative could be "standard solution", which refers to a solution with known concentration that is used for comparison and calibration purposes in analytical chemistry. Another option could be "regular solution", which conveys the sense of a commonly used or expected solution. Similarly, "typical solution" suggests a solution that is representative of a particular set of conditions or circumstances. Other possible synonyms include "conventional solution", "ordinary solution", and "customary solution". Depending on the context and the specific nuances of meaning desired, one of these synonyms may be a better fit than "normal solution".