题目

为了证明一水合氨(NH3·H2O)是弱电解质，甲、乙、丙三人分别选用下列试剂进行实验：0.010 mol·L－1氨水、0.1 mol·L－1 NH4Cl溶液、NH4Cl晶体、酚酞溶液、pH试纸、蒸馏水。 (1)甲用pH试纸测出0.010 mol·L－1氨水的pH为10，则认定一水合氨是弱电解质，你认为这一方法是否正确？________(填“正确”或“不正确”)，并说明理由： ________________________________________________________________________。 (2)乙取出10 mL 0.010 mol·L－1氨水，用pH试纸测其pH＝a，然后用蒸馏水稀释至1 000 mL听下面一段材料，回答第1-3题。 1. What is Sally doing? A. Reading a letter.B. Washing clothes. C. Making a phone call. 2. Why does Tom ask Sally and John to call him? A. He wants to meet them at the station.B. He wants to invite them to dinner.C. He wants them to visit his family. 3. What is Tom's telephone number? A. 680-6840. B. 780-6842. C. 780-7842.