问题
单项选择题 A1/A2型题
维生素C的鉴别方法不包括（）
A.与硝酸银试液的反应
B.与二氯靛酚钠试液的反应
C.硫色素反应
D.红外光谱法
E.以上都不是
答案
参考答案：C
解析：维生素C的鉴别方法有与硝酸银试液的反应生成银的黑色沉淀；与二氯靛酚钠试液的反应使二氯靛酚钠试液颜色消失；红外光谱法：维生素C分子中含有羟基、酯基，它们在红外光谱中产生特征吸收峰。
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维生素C的鉴别方法不包括（）
A.与硝酸银试液的反应
B.与二氯靛酚钠试液的反应
C.硫色素反应
D.红外光谱法
E.以上都不是
参考答案：C
解析：维生素C的鉴别方法有与硝酸银试液的反应生成银的黑色沉淀；与二氯靛酚钠试液的反应使二氯靛酚钠试液颜色消失；红外光谱法：维生素C分子中含有羟基、酯基，它们在红外光谱中产生特征吸收峰。
An old man went to live with his son, daughter-in-law, and 4-year-old grandson. The old man’s hands , his eyesight was not clear, and his unsteady（不稳定的）. The family were every night at the dinner table. But the elderly grandfather’s shaky hands and sight made this rather difficult. Peas rolled off his spoon onto the floor. When he grasped the glass, would often spill（洒落）onto the tablecloth. “We must do something about grandfather,” said the husband. So the husband and wife set a small table in the corner. There, grandfather ate in the corner while the rest of the family enjoyed dinner at the dinner table. grandfather had already broken a dish or two, his food was served in a bowl. Sometimes, when the family grandfather, he had a tear in his eye as he ate alone. , the only words the couple had for him were sharp when he dropped a fork or spilled food. The 4-year-old boy watched all this . One evening before supper, the father his son playing with wood scraps（小块）on the floor. He asked the child sweetly: “What are you making?” Just as , the boy answered: “Oh, I am making a little for you and mama to eat your food from when I grow up.” The 4-year-old boy smiled and went back to on it. The words the parents so much that they were . Then tears started to stream down their cheeks. no word was spoken, both knew what they had to do. That evening, the husband took grandfather’s hand and led him back to the family table.
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