在0.1mol/L氨水中，分别加入少量下列物质，溶液中的c（OH-）如何变化？（填“增大”、“减小”或“不变”）
（1）加少量HNO3溶液______ （2）加少量KOH溶液______
（3）加少量（NH4）2SO4固体______ （4）加大量水______．
氨水中存在平衡NH3•H2O⇌NH4++OH-．
（1）加少量HNO3溶液，发生中和反应，溶液碱性减弱，溶液中c（OH-）浓度减小，故答案为：减小；
（2）加入少量加少量KOH溶液，溶液的碱性增强，溶液中c（OH-）浓度增大，故答案为：增大；
（3）加少量（NH4）2SO4固体，溶液中c（NH4+）增大，抑制一水合氨的电离，溶液中c（OH-）浓度减小，故答案为：减小；
（4）加入大量的水电离程度增大，但溶液的碱性减弱，溶液中c（OH-）浓度减小，故答案为：减小．
| 从方框中选择合适的词,用其适当的形式填空 | |
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| The Channel Tunnel (英吉利海峡隧道) In 1858, a French engineer, Aim? Thome de Gamond, arrived in England with a plan for a twenty-one mile tunnel 1 the English Channel. He said that it would be 2 to build a platform in the center of the Channel. This platform 3 as a port and a railway station. The tunnel would be well-ventilated (通风好的) if tall chimneys were built 4 sea-level(海平面). In 1860, a better plan was put forward(提出) by an Englishman, William Low. He suggested that a 5 railway tunnel should be built. This would solve the problem of ventilation, 6 if a train 7 this tunnel, it would draw in (吸入) fresh air behind it. Forty-two years later a tunnel was actually begun. If, at the time, the British had not feared invasion(入侵), it would have been completed. Recently, there has again 8 great interest in the idea of a Channel Tunnel. If it 9 , it will connect (连接) Britain to Europe for the first time in 10 . |