Base your answers to questions 75 and 76 on the information below and on your knowledge of chemistry.

During the winter months, icy roads pose a threat to motorists and can lead to accidents. A mixture of sand and sodium chloride, NaCl, can be spread on roads to make winter driving safer. One New York town requires that a mixture of sand and salt used on residential roads should contain 25% or less of NaCl by mass. A 10.0-gram sample of a mixture of sand and NaCl was analyzed and found to contain 3.3 grams of NaCl.

75 State, in terms of freezing point, why sodium chloride is part of the mixture put on icy roads. [1]

76 Explain, in terms of composition by mass, why the mixture from which the analyzed sample was taken should not be used on residential roads of the town. [1]