The answer to this question is a bit complicated. If you are asking if a bottle of salt water will keep water from freezing in general, the answer is no. Salt water has a lower freezing point than fresh water, so it will actually cause water to freeze faster. However, if you are asking if a bottle of salt water will keep water from freezing in a specific situation, the answer may be yes. For example, if you put a bottle of salt water in a freezer, the salt will cause the water to freeze faster than the air around it, creating a sort of insulation. This can help to keep the water from freezing solid, but it will not keep it from getting very cold.